I love these videos as the original albums are kinda muddy and it's sometimes hard to hear what Gar was doing. I have new respect for him when I watch these.
Gar is/was a completely different drummer compared to most metal drummers. But I think Dirk does a pretty good job in Megadeth, he may not be the best drummer in the world but I think he compliments Megadeth pretty well.
The thing is I don't see why bands didn't do some of this stuff pre-covid anyway. Maybe not as much of it but look at Bittner, he's been very prolific on social media for a while now posting regular videos and silly things. Hatriot is the same (although not to the same calibre as Bittner) Rob Halford is the same. These people are not really doing anything out of the ordinary just because they are in isolation. Obviously it takes some effort to set up videos and post, but there is plenty of bands that could film play throughs at the like.