I work in this exact space (online grocery retailer in Europe). We're profitable and one of the few companies to be so in the sector - many online divisions are losing money and being bankrolled by the parent company with physical stores. Alternatively, burning VC money. The thing that's wrong with Ocado's technology is that it's ridiculously expensive and tailored for huge FC's (fulfillment centers). The problem wit…
I think there's a space for something in between Ocado and Uber Eats, in the 2010s I worked for a startup where you could book an Ocado style delivery slot for the next day from a bunch of different butchers, bakers, etc and then we'd send a van round to collect from all of them and deliver it to you. Annoyingly they ran out of money just a little bit too soon, I'm pretty sure if they'd managed to hold out until 2020…
There are a number of extremely difficult problems that are definitionally insurmountable on the timescales that VC operates -- paramount among them being the establishment of trust and mutualistic relationships with your vendors/stores, customers, and employees.
You are right that there is such a space, it just won't happen in the context of a startup taking VC cash.