Wow, that's weird. I don't remember ever seeing one site like that. Can you point one out? I mean, GA has been blocked at my places since 2015, and I don't remember anything ever was broken, on phone or desktop.
Can't think of any specific sites, but it's happened to me a few times. It's usually because there's bad code that's waiting on the GA init function before doing anything else.
This is why some blockers like uBlock Origin stub out the Google Analytics interface.
