then we have fewer restaurants
No, we don't. People still have to eat. If anything, we have fewer restaurants today because of consolidation in the industry and the way massive-scale delivery enables ghost kitchens that take customers away from actual restaurants.
less economic activity
Uber Eats barely generates any "economic activity." It doesn't rate against the economic activity generated when people go outside.
less diversity
Now you're just making things up. People don't become Ethiopian because they sat on their couch to eat at Ethiopian delivery compared with actually going to an Ethiopian restaurant.
a less interesting life for everyone!
Leaving your house is more interesting than being inside. It's pretty much the definition of "living."
It’s -15 C outside here and the snow is blowing sideways. NO ONE is going outside to grab lunch. They’re all ordering Uber Eats. If Uber Eats didn’t exist they’d be eating egg salad sandwiches for lunch, not ordering a pizza from a place that pays a full time driver.