vl, your misguided analogy stems from a fundamental misunderstanding of capital. The measurement of lost sales does not have to be a bijection to have a direct impact. What if only 1 in every 1000 people who copied software illegally would pay for it if that was the only option to acquire it? That's still a very clear and direct impact. Like you mention, a person who is paid per lawn mowed is also definitely directly impacted by the loss of revenue.
However, what about the person who owns the lawn services company? It is money out of his pocket too, when someone doesn't pay, and he spent the vast amount of resources to build the business. For a large company it may not mean much at all to his bottom line but you can't really believe that it doesn't affect him, do you? A lost sale is a lost sale. He lost revenue, regardless of how little a fraction of his total gross it was. So you could have or would have mowed it yourself, you say? Well, you didn't. Maybe he no longer actively manages the company but sails around the world on a yacht and puts in absolutely no labor and immediately takes out any resources the company produces. It still makes no difference, you still owe him and he still deserves to capture any bit of return on his investment he legally can.
If that doesn't jive, how about the following example: pirating software is similar to a tenant skipping out on rent. Just because the builder turned landlord didn't do a darn thing to improve or manage your apartment in the last 10 years, since he originally built it, does not mean he isn't entitled to receiving his fees for your access to his capital. He still paid Y for the building and deserves to get his X each and every month from anyone that *chooses* to live there for as long as he owns that building. It has nothing (nothing!) to do with how much effort or resources he may or may not have or ever will put into the building. It has to do with ownership. If you created it, bought it, or otherwise own it, generally speaking, you also own the right to say how it can be used and at what price. (period!) Buyers make the choice to accept or reject those terms... and if you try to squat in his building he will have the Sheriff toss you out on your butt.
Finally, your summary statement: "copying doesn't have the same direct impact to the vendor as theft, and copying does not necessarily imply a lost sale." implicitly acknowledges that while (1) copying doesn't have the "same" impact, and also (2) does not "imply" a lost sale, it still has an impact on revenues for rights owners. Considering that you aren't the rights owner in this case, you don't have the right to classify how significant that impact may be in real or intangible terms. Sorry, but that's the bottom line. Think it's unfair? Go create something. Then you can release it free if you like.