The ARM chips in later iPhones and all M series Macs physically don’t have the hardware to run 32 bit software.

Should they still be supporting PPC software? 68K software? Why not old Apple // software for good measure?

Right now the last time I counted in 2012, there were 12 ways to define a string in Windows and you had to convert back and forth between them depending on which API you are calling. There are so many one off hacks to keep Windows running (see Raymond Chen’s blog) it’s a house of cards

I don’t think dropping legacy support is due to boredom. It what allows them to keep moving forward without being saddled by every decision from the past.

How long should they have kept PPC or Classic support?

Microsoft is in a funny position. Backward compatibility is seen as a competitive advantage, especially in the enterprise market. However, it’s that very compatibility that makes people avoid adopting new technologies, because why bother? We see Microsoft throw so many things against the wall, and almost nothing sticks. Meanwhile, Apple tells devs to jump and they ask how high. Devs know Apple is going to cut support, so its update your apps or be left behind.

To really make a change, a person needs to be all-in. Dual booting Windows and Linux/macOS, for example. This is a sign a person isn’t all-in and they don’t really make the change, or it takes significantly longer. When a person goes all-in and burns the boats, they are forced to find new solutions and make the changes needed to make the new thing actually work.

It’s been half a century of Apple. At this point if FireWire, Flash, and a half dozen other things didn’t convince you that Apple deprecates then removes old functionality pretty rapidly I don’t know what to say.