They can never “close the loopholes” entirely, because there are customers that want machines with zero access to public Internet (embedded systems, national security, etc), where a Microsoft account is an absolute non-starter. Closing all the loopholes would be abandoning those market segments (many of which are already trending towards Linux/etc anyway)

I suppose they might make it mandatory unless you have some special version of Windows which is hard to buy (like LTSC). But make it too hard they risk that market. Anyway, now bypassing it involves opening a command prompt window, only the more technical users will do so, and that’s a small enough minority they probably aren’t missing much.