I usually use my Macs until I feel an upgrade is worth it (I can sometimes get five years out one), and then upgrade and give the old one away to someone who could use it. The cost for me is really that I'm not going to want to keep my current MBP (bought at the end of 2017) for as long as I usually would, just because they keyboard sucks.

I absolutely agree, they should offer a significant discount to people trading them back in to get a replacement model.