I don't think this is very much about modern projects. Developers want to use 64-bit. It's more that removing the libraries breaks legacy 32-bit stuff that simply can't be updated.

The steam client should be upgraded, though. I understand it has to do with their ancient web view library not doing 64-bit, so they would have to change it and possibly mess up some of the layouts and overlays. But they went ahead and changed it on macOS anyway, so you know it can be done.