And that is exactly what Meta wanted. They don't want to rely on Play Store, and they managed to ship tens of millions of devices without it.
For gaming it's not an issue but if they ever want to sell people on the idea of it being used for productivity, that flat android app market would be a big factor. They have recently started their own toolkit to build/convert regular android apps to HorizonOS so they maybe hope to beat Google at their own game, but we'll see how that turns out