New Murata lora chip with integrated STM32

why is a bootloader not standard feature for these other boards?

I know :) I think one reason is it's a pretty steep learning curve to get it working - I spent a long time bashing my head against a wall getting it working, and a lot of companies aren't that bothered.

However RAK have said that they will be adding one to new boards, so we'll see what happens...

Group buy

That may well be possible if enough people are interested. I'd have said the RAK813/RAK815 was probably a better contender for that though. The Quectel modems on the RAK8211 are pretty pricey all by themselves, so it may be that RAK don't actually have that much wiggle room :)