Okay, first, I appreciate the thoughtfulness behind this letter. But how you purchase comics is really up to you. Buying comics second hand from a dealer or pro or at a con is absolutely contributing to the industry.
The tpb thing is kind of how much mass publishing works. A hardback or collection is printed to a certain order, when that sells out, they print something else, or they may do further printings.
But they don’t keep everything in print forever, it’s just cost-prohibitive.
So it does created a secondary market that can be a little brutal. Some great books are cheap and easy to find, and some are rare and expensive.
For you, it sounds like a convention might be a good choice, there are often dealers with huge amounts of tpbs to sell very reasonably, I always end up with an armful if I allow myself to stop and shop.
Or you might consider digital purchases. I prefer hard copy but it’s good option for some.