Every restaurant thinks they're special and they all want their own app. So if you have a regular group of restaurants that you order from you're installing potentially a dozen apps, all of which are probably riddled with spyware and security holes.
Plus, the restaurant loses the ability to completely control the experience the customer gets. If the pizza sits around for half an hour before it gets picked up, gets to the customer cold, and then the customer complains, how is that the restaurant's fault?
I'm not negating your point: it is a pain and a risk to install a dozen apps. But I also understand why they do it.
I do not want your app of crap!
And as a user of UberEats, all my perceptions are wrong: The good experience I have is not valid, just an illusion, and I am dumb.
And literally all of the 100M users of UberEats are also wrong, and pretty crappy humans.
OR maybe you're just blinded by your ideology. Who knows!?