The answer feels pretty obvious. This whole thing was a vaporware pump and dump scheme to rip off investors. No one needs 500 million dollars and 7 years to build a pizza robot; but that's a lot of years of salary and making PowerPoints. Legitimate productive cost effective engineering strategies for their core product probably left the discussion space after they raised their first million dollars of funding, and all the people actually capable of solving tasks left soon after the company was taken over by bozos
Once you have the money your kind of wedded to the idea… if it was weird or audacious you have a certain level of follow through necessary to “save face” and be believed next time you present an idea and promise it’s worth what you claim it might be, hence why a dumb idea like this pizza van, took years to finally die.
The follow through on the idea requires believing in it… or at least convincing everyone giving you money that you believe. Because if you don’t believe it’s really able to make money, then your basically lying to them.
Even if there is some mechanical issue, why not bake the pizza on a 'bed of nails' so the cheese says put?
It seems like there must be a dozen solutions available. Was cost prohibitive?