Overwatch is pretty casual. It is tuned for spectacle, and the abilities work out such that most reasonably non-bad players get a steady trickle of moments where they get to be the “star” for a scene.
It isn’t really a core problem, just a different type of game.
StarCraft 1 has had no balance updates in over 20 years, and the game is doing great.
StarCraft 2 has had no balance updates for like a year or two, and it was slowly killing the joy of the game for everyone who bothered to suffer through it.
StarCraft 2 was designed to be a game where the meta has to be shaken up occasionally; StarCraft 1 ended up more like chess: if you tweak a rule once in a century (or the Internet-equivalent of a century), it's big news.
Different games, different needs.
Meanwhile: Fighting Spirit
For games like Rocket League, CSGO, Overwatch, Apex, etc. The teams are even no matter what (skill aside). Meta still exists however, as anyone who has played multiple years of any of these games sees. Expected attacks, combos, and preferred approaches change over time as people discover weaknesses to the existing metagame and exploit them.
Not to say Rocket League has vastly changed in the last 8 years (I've played for 5 of them), but it's definitely different and a little updated.
Edit: Not to mention Rocket League rotates special game modes regularly for this purpose as well.