I wonder if part of this might be everyone who uses a 58 or 57 live asking their FOH engineer what mic should I get for recording at home? The FOH guy knows the Shure works and especially right now money is probably tight , so the SM7 is the choice of the day. Plus unlike most studio condensers it can be handled a bit.
I've been amazed (probably naively) at how ubiquitous the SM7B is in pod casts and "from home" concerts since the lock down - the only mic that seems to come close in popularity is the Blue Yeti, which is very actively marketed for Internet use, etc. yet still seems to be a distant second choice. I think I've only seen one RE-20 and a couple of 58's (or look alikes) otherwise. And for the concerts, you would think that most of these musicians have access to a wide choice of mics and good advice on selection. I'm not sure if the popularity is down to the influence of Joe Rogan, et al, but it seems to have reached a tipping point of some kind.
I don't have any axe to grind against the SM7B, just surprised at the lack of diversity and curious about the popularity of this one mic. In fact I'm not sure I have a point of any kind - I was just driven to flaunt my (naive) amazement for some reason. Probably cabin fever.