Not sure about Amazon datacenters, but I know an actual person in real life who went from an unskilled Amazon warehouse worker to a full-time SDE at Amazon with zero previous coding experience or a relevant degree. All in a 1-year timespan iirc, simply going through one of the training programs that their warehouse offered.
Apparently, those on-the-job training programs that Amazon offers actually tend to work at times. And of course this is just a single datapoint not indicative of anything, but it kinda shows that those programs might actually work to a degree. I don't doubt that their success rate is likely not even close to 100%, but if it worked even for a chunk of the people attempting it, it is still something.