The logistics of mobile distribution of a fast expiring product are much more complex than you think, and spoilage and expiration losses need to be acceptable at some level to proceed. I think in the case of the vaccine, the latter is well understood, but no one wants to be responsible or held accountable for any vaccines expiring, due to the optics of the situation.

I worked on Uber briefly while we tested the early version of UberEats which involved distributing burritos in San Francisco during lunchtime.

The restaurant making the burritos would have to pre-make the burritos between 7am and 10:30am and ensure that they were made available to supply depots around the city.

From 11am-1PM we would accept orders in the app. An order would be dispatched to a bike or walking courier who would walk the burrito from the supply depot to the consumer who ordered it. The goal was to make sure you had a hot lunch and could get it quickly.

When it worked, it was awesome and it helped validate the consumer demand very clearly. But we lost a lot of burritos due to spoilage and no amount of data analysis and better supply positioning could make up for it. It was also not at all economically viable to bake in a 20-30% loss rate and price the burritos high enough to grow as a business. People will pay a lot for on-demand food, but we found they were willing to wait 30 minutes (if it came straight from the restaurant) and pay a little more (if we dispatched with more courier delays), so the on-demand marketplace was born.

With the COVID-19 vaccine, right now I think it would be political suicide to accept a 30% daily loss rate on expired vaccines, even if it meant we vaccinated people twice as fast. There would need to be a higher vaccine supply available where vaccine expiry becomes as moot point as a spoiled burrito.