He kind of touches on this in point IV, but never mentioned specifically: the cost comparison is not AWS vs ovh. It's fragment-of-EC2 vs ovh. If you need a predefined small number of VMs and no other functionality, it would be silly to go with AWS. But on the other hand, if you want a set of servers of a given class spawning on demand, with traffic coming in via load balancers, with integrated certificate and DNS man…
It's about economics not accounting.
Once you get into cost comparisons you've already lost. AWS is purpose built for an accounting narrative.
To illustrate what a dead end accounting is, accounting can't explain things like, "I spend money today to possibly make money more than 1 year in the future." That's basically every startup and accounting doesn't have a story for it.
Of course a free tier looks good accounting-wise. How does one "account" for lock-in though? If you can't figure that out you will not convince bean counters to consider alternatives.
And good luck teaching economics (as opposed to accounting) to bean counters.
Here are a few compelling explanations: the cheapest bid (i.e. free tier) is always the worst one. Some people are so addicted to accounting storytelling - as a way to organize their world, a whole philosophy - they are actually always convinced the cheapest bid is always the best one.
Another: AWS is so overpriced, the $50k you spend on developing against AWS services to use $500k of "free credits" will deliver less value than $50k you spend developing for a single vertically scaled beige box computer with simple ergonomics and running it.