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.
Well let's look at its timeline
Howard confirmed in 2016 they ES6 was going to be made.
The E3 announcement trailer was in 2018.
The same year they said it wouldn't start until after Starfield
In 2021 Howard said it was in design phase
2023 they said it entered active development
2024 they stated early builds were playable
2025/Today they said it's the main production focus
10 years between Todd saying it was going to be made and finally being the main production focus. So had they not put their weight behind Starfield its likely ES6 would have already been out or getting very close to release.
The underlying issue here is how Bethesda allocates resources between its titles. They should have created studios entirely for Fallout and one for TES and MAYBE a 3rd for side projects like ESO, F76, and Starfield. Ultimately this is a mix between Phil Spencer and Todd Howards fault. Phil should have stepped in and made the executive decision to branch the studio and Todd should never have allowed the mainline games to become secondary to side projects.