Metaverse != Horizon Worlds
Mark's metaverse is very specifically a shared virtual physical environment. Yes you're going to pay to enter spaces and have experiences and buy clothing... but Horizon Worlds isn't an app on the platform. It is the platform, it is the metaverse, everything is happening within it in Mark's vision here.
Metaverse == Horizon Worlds
The Quest operating system, and the Meta app store, are obviously not the metaverse... the metaverse is a universe of shared 3D spaces. That's Horizon Worlds. The spaces are the "worlds".