Normally yes, but NYC is sort of the Big Exception in the US - it's the only city in the country where the density is so insanely high that I can imagine niche delivery businesses surviving.

We've seen this with eBay Now - the economics are sustained by limiting service to only zip codes with sufficient density.

I agree. The main problem with the original idea, IIRC, is that the product is cheap and heavy-- low margins and high shipping costs. The consumer was simply better off getting it at the store.

the ads i've seen in the subway are from wag.com, which is indeed part of a generalized delivery service.