The games that survived for so long are simply that good (so it's basically survivorship bias). There are plenty of new indie RTS games on PC, the vitality is definitely there. But there's no longer big publisher money behind it like in the heydays and without big marketing campaigns those games are much less visible.
But if you search a bit in the RTS section, there are definitely some gems on Steam (e.g. Northgard comes to mind, and currently I'm having a lot of fun with Timberborn, although that's a city builder, not a competitive RTS). Oh, and WARNO, even if it still has a lot of early-access roughness.
But if you search a bit in the RTS section, there are definitely some gems on Steam (e.g. Northgard comes to mind, and currently I'm having a lot of fun with Timberborn, although that's a city builder, not a competitive RTS). Oh, and WARNO, even if it still has a lot of early-access roughness.