Maybe. Maybe? I doubt they're motivated by malice or laziness, but nobody in this thread can say one way or the other. What I can say with high confidence is that unless we're in the meeting room at Apple we can only speculate based on little to no hard information. It's entirely possible that there are sound engineering reasons behind what they've done.

AMD64 is going to be around for a very long time; any developer that is having difficulty migrating code from i386 has more fundamental problems than Catalina.