They'd probably do glasto as a one off (although they are meant to be broke at the moment, so trnsmt could be a good extra dates to help get a paycheck in)
I am saying there is a clear shift across the board to earlier announcements since Covid as a result of the world changing quite a bit.
This is evident for all festivals in the UK and for gigs overall. This is the point. Who knows maybe it will be announced in January but it looks pretty unlikely given every other weekend festival will have announced by mid december!
Thanks for letting me know about Metallica being announced in 2014, not sure we knew what covid was then though.