I think it's pretty absurd that Grubhub and Uber take such a large commission for what amounts to pretty basic software.

But, I bet this site isn't getting much traction because it has no marketing budget (because it makes no profit).

I mean... and also an entire international coordinated delivery network, apps that work on all devices, background checks, vehicle registration and checking sites, marketing, huge expensive legal departments, etc. The original algorithm behind Google search was also "pretty basic software" but there's a lot more that goes into building a successful product than writing some code.

Why does a local restaurant care about an international delivery network?

apps that work on all devices

If by all devices, you mean iPhone and Android. Some services like Uber Eats are either not available in a browser or offer reduced functionality in the online version of their service.

background checks, vehicle registration and checking sites

It has been demonstrated many times that this is not true.

marketing

Marketing of a third party service, yes. Marketing of restaurants, no. Thus, this point is useless and arguably even detrimental to the restaurant.

huge expensive legal departments

Which does not provide support to the restaurant and thus is useless to the restaurant.

In fact, all these apps offer restaurants are vastly increased costs for minimal if any benefit.

So Uber does this but grub hub/seamless does not? The delivery folks who work for the restaurant do the deliveries for seamless and grub hub orders, at least in the NYC area.

Edit: I see now that grub hub has gotten into the business of managing the delivery as well, at least in some cases.

There is no money to be had in actually being on the hook for having the assets to do the work. It's way easier to pawn off the depreciation to the naive sub-contractor, and pocket the middle-man's cut.

This is the key behind almost every commercial "tech" innovation. Exploit economies of scale by positioning yourself to extract fees from transactions that were not previously subject to having fees extracted. If that means facilitating more transactions than otherwise would have before so be it.

Stopping right there is enough seemingly for many business minded folks in the sense that new transactions = good; but I'm starting to realize there is definitely such a thing as toxic transactions, and it seems way more difficult for some reason to get this across to folks.

Then again, I'm getting older,and the rest of the world is becoming by and largeyounger than me. So that perspective may have more to do with me being a poor communicator than anything else.

Sure. Why don't you make a competitor then? Get yourself bought for $$$.

My guess is you'll discover it's far more difficult to onboard customers (restaurants are the customers) and consumers than you seem to think. Further, once it's mildly successful, it turns out maintenance is tough.

Edit: Looks like the "in a weekend" assertion was retracted.