Yeah, I was thinking about Karl Lagerfeld and the H&M collab which was the first and I remember there was huge surprise that it went up to a size 44, which would be more like a 46 (18/20) now. Iirc that was at H&M's insistence as that was their standard size range at the time, making it one of the few high street shops that catered to these sizes without it being plus sized. Looking where we are now, I'm fully expecting plus size brands to branch into normal sizes now instead of the other way round, loads already start at size 40 or 42.
I don't know how much impact the pandemic will have on purchasing behaviour once it's over. I think the next change will really be down to innovation in technology in fabrication. I did notice you can now buy printed mask patterns on a roll, you just cut them out and match them up (they tended to be the fun photo printed things like chimp mouths), it's really easy and more straight forward than traditional patterns. I can definitely see some DIY garments being sold like that as the general DIY trend is ascending.
In the first wave all the Harry Styles groupies got obsessed over a J.W. Anderson patch cardigan he wore, which looked very homemade and attempted to replicate it with lots of online tutorials. In the end J.W. Anderson released the pattern in pdf and with a YouTube tutorial, I can see a lot more of that happening to build a more intimate relationship between brand and audience that could potentially buy in at the lowest price items (perfumes, cosmetics, and accessories) which accounts for most of their financial existence.
Anyhow, I ended up buying some Thebe Magugu bits in the sale as it was an extra 20% off, the high neck 'pie crust' Victoriana shirt photographed previously and a skirt. From another brand I got a small summer handbag as I find leather overly formal most of the time in warm weather now, I figure I need to make it an inner bag though.