No, it is a cost imposed on someone without their choice. One doesn't impose costs just so they can lose money.
I'll rephrase. Pollution is a byproduct of purchased raw materials and energy, and therefore consists of materials that are paid for. If you generate mercury waste, you paid for that mercury to begin with, albeit usually in conjunction with something else the company wants. Nonetheless, you buy the whole ore or whatever it is you are processing. The pollution generates no income. Thus, ultimately in a system-wide view, it is something the company has bought and obtained no return on.
There's not much you can do with something like mercury, unless there's a sudden surge in demand for old-fashioned thermometers, but other byproducts may contain things that are rather more useful. Even with mercury, there's probably something you could sell it for.
(I am not considering regulatory costs in any of this. Regulation, if done correctly, should be a pressure on a company to do its best, to overcome the resistance towards change. In other words, nothing more than the minimum force needed to overcome inertia in a company, where people choose the easy solution rather than the right solution. Regulation is NEVER done correctly, as such it is not worthy of consideration. I will not lower myself to considering substandard processes. And since correct regulation produces the same result as a fully-optimized company, correct regulation has zero impact on such a company.)
Which everyone bothers to do to some degree.
Not in my experience and I've worked in a wide range of companies. They've usually not been successful companies, true, but there's not that many industry giants and if I assume that my experience is a fair reflection of the percentage of good vs wannabes, then most companies aren't optimizing resources. Workflows, maybe. Personnel, maybe. Actual resources, not so much.
And let us keep in mind that the cost of cleanup != the cost of the pollution externality to the rest of society. It frequently is much higher.
I guess I should add that again I'm looking at a system-wide view. The cost of not cleaning up can damage the health of locals and employees, damage the environment (which, in turn, can impact the company - the metal-eating bacteria in the Peak District from pollution release by Industrial Revolution-era industries are playing merry hell with just about everything) and so on. True, this all takes time, hence the idea of looking at cost over two and a half decades rather than three months. It's not direct damage, but it is still damage that impacts the company even without considering regulatory costs.
That doesn't make sense, since the parameter we're changing is amount of clean up costs not the company's degree of compliance with regulation. Obviously, the optimal from the company's point of view here is zero clean up costs. But we already know that results in considerable costs to the rest of society.
I regard regulation as a bunch of BS, so I'm ignoring it. If a company is making the most out of what it has, it is guaranteed to be in compliance with all sensible regulation. Neurotoxins in the food chain damage employees and lower effectiveness, increase sick days and increase insurance costs to the company. It makes no economic sense for a company to mutilate its own staff. But since everyone in the area eats from the same food sources, keeping the staff healthy and mentally at peak will involve keeping everyone in the community healthy and mentally at peak. Especially in the longer-term, since the next-generation of employees will be from the "everyone else" in the community.
This goes for the other considerable costs to society, too. New Orleans was as badly struck as it was by Katrina because industries had altered the river delta in a manner that destroyed sand banks and other naturally-occurring protections (such as trees). By damaging and polluting the environment, the cost to society was certainly vastly greater than the costs to the industries - I won't dispute that for a moment - but I would nonetheless argue that the industries inflicted damage on themselves that exceeded in cost the amount it would have taken to not cause the environmental damage in the first place.
In other words, if they'd spent up-front on NOT polluting and wrecking havoc, they would have had a higher initial cost but a lower long-term cost. ie: they would have made money by acting in a manner that would ALSO have prevented one of the worst natural disasters in recent American history.
I contend this is a common pattern. Aging nuclear reactors are less efficient than modern third-generation ones at converting fuel to power. They also generate more nuclear waste (since there's unspent usable uranium there - enough that it's commercially viable to extract it and reprocess it). So you end up with a greater waste problem AND less power (and therefore less money) than if you replace the reactor. The reactors are all well over their designed lifespans, making them unsafe, but by looking at too small a time window, the cost of replacing a reactor is the largest factor in the equation and so they aren't.
By looking at a very long timeframe, the cost of buying vastly more uranium than is actually used, the cost of refining uranium you're only going to dump, and the cost to society as a whole of dumping that waste uranium, combined, overwhelm the cost of actually building a new reactor that does more and wastes less. After that, the more efficient conversion to electricity plus the reduction in unspent fuel are all variables in the 'sheer profit' category. So, again, helping the environment actually makes money in the long-run.
This, I believe, can be generalized to all businesses that create pollution. The cost of a superior approach is outweighed merely by the profits that superior approach can generate.
Stop for a moment! Why should this even matter? We're talking about a world population of 7+ billion people and many trillions of other organisms. Why should I be so focused on reduction of pollution as a path to profit?
Because the number one factor in company decisions is whether it makes money or loses money. You will never convince companies to do what is morally or ethically right, but you can certainly convince them to do what will beef up their bottom line.
There will come a time when everything doable has been done. THEN it is sensible to look at the ethics and morality, and the broader global picture. The world is one single system and no part of it can ever, really, be totally isolated. What is done one place affects EVERYONE.
I do not believe that that time has yet come. I also believe that companies are sufficiently used to dragging their heels that such an approach will meet too fierce a resistance to overcome. I believe that, right now, the correct strategy is to appeal to the basest nature of the businessman, to show how they're losing money by being cheapskates and polluters. That is an argument I believe they can listen to and comprehend. Once they're used to changing and adapting, then it makes more sense to coax them into looking at the global picture.
For now, though, what matters is getting them to do something and to stop obstructing efforts to improve on the efficiency of technology.