I watched the first one when it was 'New' and quite a few of the 'Celeb' ones over the years... but even though they tried to make it spangly and new, it just became a bit stale.
Back to OP, where will the supply of "Celebs" come from now? I once saw Christopher Biggins in a Pantomime when I was a kid... so I'm sure I'd have qualified.
I will admit to never having watched , Love Island, Towie, The only way is through Essex, avoid Geordie girls and such but isn't that where they come from now.