I think his is underestimating how big HL3 is as a part of gaming culture. Half Life really wasn’t part of my generation, but I grew up with HL3 being memed constantly. The constant fake leaks and rumors have kept the idea alive. Just a couple months ago I saw a lot of people genuinely believe it was going to be announced during The Gaming Awards thanks to a leak that Valve would be present. Every gaming event has chat full of people spamming Half Life 3 memes. Plus, Alyx got a lot of younger gamers to play the series.

If Half-Life 3 were actually announced the hype would 100% be there, even if most of it will be from people who had never played the games.