Your first sentence is factually false. If it were true, wind energy would be phenomenally profitable right now
You may need to work a bit on your reading comprehension. If I would have stopped writing after my first sentence, you might have a point, but my second sentence (starting with "only") nicely explains why what I said doesn't make wind energy phenomenally profitable. Also, I said "very little" (not "no") and "maintenance problems" (not "maintenance requirements"). The difference being that, while everything requires maintenace, it becomes a problem if it jeopardises profitability.
All that said, I do admit I applied a slight bit of hyperbole (but nowhere near "factually false"). What I meant is, one can make a turbine that is lighter on maintenance. It will be more expensive and and yield less power that its competitors, so you'd need more surface area and upfront investment for the same power output. It's even possible that a complete wind farm of these things will require just as much maintenance per unit of power because of having more turbines. Even assuming this isn't the case, in the real world, upfront investment is commonly made possible by loans, which have to be paid off. And business people are not highly interested in investing in anything that won't turn to profit in the next 10-15 years (unless the promise of profit is huge). Higher upfront investment for the same yield is a competitive problem; your "it has effectively no other costs" is an oversimplification. So all these economic factors taken into account, turbine design is what it is, with a maintenance cost that - in an ideal world - would lead to the highest possible profit for wind farm operators (within physical constraints). If maintenance costs are far beyond that sweet spot, then someone somewhere down the line didn't do their job right.
As for wind energy being more expensive than coal, I never said otherwise (see my opinion on energy policy). The problem with coal is that you're taking relatively pure carbon that is buried underground by nature, or in other words sequestered by nature in the most efficient possible form, and converting it all to CO2. I'm very pessimistic about the economic feasibility of sequestering the CO2 output of a coal plant; what is sure is that the current (admittedly immature) sequestration technology makes coal unprofitable altogether. And if you just let the CO2 go into the atmosphere, some people will argue that the ultimate economical cost of coal, including the economic effect of climate change on future generations, is far higher than wind. One cannot say with 100% certainty whether that's true or not, but current data strongly suggests it is, and there's the precautionary principle...
I'm very much anti-coal; the environmentalists that are fighting for a quick and complete end of nuclear power are fighting the wrong battle and I'm just as angry about it as you are. I do, however, believe (again just like you) that something needs to be done about those very old and unsafe nuclear plants (represented in large parts of the world by the GE Mark I), and about the on-site storage of spent fuel. The gap left behind by removing coal (and very old nuclear plants that cannot economically be made safer) should be filled in by all possible means that emit as little CO2 as possible, perhaps including newer and safer nuclear technologies for base load, but also solar for catching up the day peak in hot regions where a lot of air conditioning is used, wave power, wind in regions with sufficiently consistent and strong wind, and where necessary a little bit of biomass and natural gas to fill up lulls in wind (yes, even though the latter emits CO2). And a modest increase in electricity cost is an acceptable price to pay for that.
Finally, I don't believe a huge baroque scheme of government intervention is required to implement the above solution. Simply put into place a cap-and-trade scheme, or else a carbon tax (the proceeds of which may partially or fully be used to subsidize and/or research better technologies). Also, become a bit stricter about nuclear safety. Beyond that, the free market will automatically evolve to the situation I sketched above.