look up PbtA and Savage Worlds. They’re talking about entirely new game systems.

I've played a variety of systems, including Alternity and GURPS and Megaversal and World of Darkness and FATE. I'm not arguing that d20 is the definitive system.

they’re arguing for equally good game systems made by independent developers which are also roleplaying games, but they encourage different playstyles

In my experience, the thing that encourages the playstyle is the setting far more than the game mechanics. Using the WoD framework - Vampire, Werewolf, and Mage all run on the same fundamental system. But Vampire is inherently a political game. Werewolf is heavily tilted towards raw physical combat. Mage can't help but wobble between mystery/thriller and long debate about metaphysics. They're all built on the same core framework. Even then, you can absolutely play a Gunslinger Mage or an Eldrich Researcher Werewolf, if that's the game you're playing in.

The thing that really draws people to Wizards of the Coast / Paizo tends to be the volume of players and the volume of content. Paizo, in particular, is really good about releasing new adventure modules annually. That's the grease a lot of tables need to get going.