I have an M1 MacBook Air and I love it. But it's no replacement for my Threadripper 1950X / RTX 3080 for work/gaming.

x86 gives me choices. I can run Windows, Linux, etc. With M1...I'm at the mercy of Apple's closed-system. Sure, there are folks working on getting Linux working on the M1, but there's no guarantee that Apple will let you keep running/installing Linux. You're one Apple firmware update away from bricking your device/alternate-OS.

Who says Apple will be the only vendor of successful ARM desktops? It seems like it's only a matter of time before other vendors catch up. The point is simply that Apple demonstrated the viability of ARM in those use cases.

Windows on ARM laptops existed long before the M1 and they didn't catch on. It's Apple that is late to the party.

But like you said yourself, they didn't catch on. Therefore I wouldn't describe those vendors as "successful". Apple was the first vendor to achieve that. It may be that the Qualcomm chips used by the majority of those devices just aren't competitive enough to replace desktop use cases.

Apple Silicon != Windows on ARM.

Apple Silicon is a product line-spanning transition to home-cooked ARM CPUs. Windows on ARM was an experiment designed to run alongside x86, likely intended to fail. As for the "successful" bit, I couldn't frankly care less. You're welcome to measure success by whatever metric you choose, but the switch to ARM has ostracized me and many other developers I know (some of whom are Apple users currently).

In other words, ARM is good at watching Youtube videos at low wattages: who knew? (Answer: Everyone who used ARM for this exact purpose before Apple did)