What OP describes is an anomaly that should be easy to fix by any platform, and if they are smart, they will fix it - or decay slowly (at least I hope this is what will happen, and that they take Amazon & Google Search with them too).
Quality is just natural progression. Good food survive and bad food keep being replaced with new restaurants. Just like traditional restaurant industry.
Quality food and drink are extremely sensitive to timing, as in minutes matter, and if you are talking about a developed country keep in mind that consumers are sophisticated and getting more so by year, they are aware about it and pay attention to it and this will be reflected in the market.
If convenience really trumped everything we would all be eating dry instant noodle out of the packaging. Delivery may remain a thing in the suburbs but it would always be a second rate option.
It's not just low quality crap restaurants that do this. Like anything you get what you pay for. Better restaurants pay for better quality stuff but still mostly prepared by Sysco and finished at the restaurant.
I’ve worked back of house at a “almost michelan star” restaurant (best rated in town!) and even though the chef did actually go to the butcher for meat cuts, we still had a Sysco truck stopping by every day.
And that's for everything. Farmer growing wheat/chickens, cook making batter + cooking, syrup, banana growing, spices, clean up, waiter, etc.
Realistically if we're talking about just the restaurant bit there can only be a few dollars of labor and therefore maybe like 5 minutes of labor at most. Only way to achieve that is through scale.