I've used vim every single day at work for ~12 years. With the kids I rarely do at the weekends but I happened to be setting up my .vimrc on a relatively recent laptop this afternoon. Big impact on my life for a guy whose name I never knew until 2 minutes ago.
I use Vim since 31 years. Started in 1992, on Amiga with Fred Fish disks. I use Vim daily at work since 20 years. It's like a second home for me, a familiar tool which makes me confident that it'll help me manage whatever task I throw at it. I never had the pleasure to encounter Bram to tell him how much his work helped me throughout the years. I should have sent a "thank you for your hard work" mail when it was still possible. Now I can only send condolences. And some money to the ICCF. That's the least I can do.
You definitely have a point about the "thank you"-messages. I don't think I've ever sent a message like that to the author of any software, but I think it might be time to start, especially for software that is the product of (or spawned from) the hard work of a single person or a small group.
Recently I used testdisk/photorec to recover photos from a dead sd card. Made a small donation and sent a big thank you to the developer. As you said, sending appreciations and thanks for someone's hard work is an important thing to do, and if applicable, small donations. Right now I'm quite ashamed I've never did the same for Vim while Bram was still alive, especially since Vim is one of the most important tools I daily use :/.