I don't know that G5 schools can do anything.
However it's not all doom and gloom though.
The flipside is this.
Lots of P5 players will be transferring down to get playing time as well.
No way UNLV lands a recruit like Harrison Bailey out of HS. But guys want to play, and sometimes their only path to playing time is to transfer.
A lot of 3* guys that UNLV would have been happy to get in the past that landed at P5 schools will hit the portal when they can't beat out 4 and 5 star kids.
Initially I thought the portal was a death sentence for G5 schools.
I'm not so sure now. Not saying it helped G5 schools more or even evened the playing field, but I do think the talent will remain about the same overall..