I actually mentioned a similar thing just the other day as part of this UX topic
There is also this open Feature request I spotted in the Related Topics as well:
(Not a lot of traction though, but it shows we’re not alone )
I think one of the counterarguments is to not overcomplicate things for new/occasional users, but a bulk select is quite normal in an email app for instance so it’s unlikely it’d be something they’d never seen before (and already exists on the new/unread views, albeit for a slightly different use).
Even if it was deemed to be too much for ‘everyone’ it could still be kept out of the sandbox for TL0/TL1 and opened up to TL2/TL3.
Though I should also mention the category level notifications as well, just to be sure that’s not relevant to your current situation?