"Investors are not stupid, and IF (not sure if they do push this TBH) they are insisting that a company uses Amazon, Microsoft or Google, it's for a good reason."
Firstly, VC investors are stupid. That's why 12 in every 13 of their investments tanks.
Secondly, when I was getting VC funding back in the day it came with one particularly odd string which was that we had to host on Dell hardware because Dell were giving them backhanders. They even suggested that we should not try to optimise the application too much as they would like to ask Dell for bigger hardware and therefore a bigger sweetener (basically Dell wanted to boast about installed CPUs).
None of the things you listed are of any real value to a startup; even uptime.
VCs know nothing. If they did, they'd do it themselves or have a decent hit-rate.