Optix, it's people like you that scare me sometimes... that sounds like fun.
Honestly, I thought the US already had something like this...
Most NON-grocery stores in the US offer online ordering and in-store pickup, but not even Walmart offers it for groceries. The only stores I know of that allow online ordering for food are Costco and Sam's Club, but even then I don't know how they handle refrigerated items, and you must still go pick the stuff up at the store.
I may be the odd guy out but I DO enjoy going to the supermarket... at least the upscale ones.
The stuff one can find is always interesting, and there are always new foods or things I'd not have thought of before that were typically found elsewhere in the world. The wider varieties and fresher produce & breads are a big plus too.
Which brings up my issue with online ordering... if I ordered a pineapple and it showed up anything like what Walmart usually stocks, what's the buyer to do? I enjoy a good pineapple, but "black & brown" pineapples are not one of them. I've seen a table full of completely blackened pineapples on multiple occasions at a walmart, even. Walmart is nothing but consistent on that score.
I'm not sure I'd ever trust an online store to give me really good produce consistently. Not to mention I know which brands sell consistently better quality pineapples. Given that almost every supermarket I've seen rotates produce brands every week, people truly won't know what they're ordering when it comes to produce. Honestly, produce is the largest reason for even making frequent trips to the store.