That's going to be the case for all Valve games at this point. When Left 4 Dead 2 released back in 2009 I was 18 years old. The 2027 graduating class was born between 2008-2009. So hypothetically, anyone who had a kid in my class right after my graduation would have grown up playing Left 4 Dead and now their kids would be playing it.
Aside from Alyx, I highly doubt we will ever see any new major titles with the their older games at this point.
Because he's not the publisher Sony is and they ultimately control the budget and marketing which includes adding Denuvo.
Only thing he can do is advocate against it.