I have lots of USB-A devices, so I get what you're saying. But converters are pretty cheap and seem reliable.

And Apple has a long history of making this change ahead of the rest of the market. It's been years since they've move to all USB-C in their laptops, so IMO, it was only a matter of time.

And yeah - upgrades are awful price wise. From what I can tell, it's basically only worth it to buy base models unless the machine is making you money. Hopefully they upgrade the Mac Studio to M4 down the line.