Five years of experience, most recently at Atlassian, until the layoff two months ago. Since then, by his account: Amazon, five rounds, rejected. Two startups, three rounds each, rejected. Microsoft, where the high-level design and low-level design feedback was good, but the data structures round went negative after he accepted a hint.
He has been studying every day. The pattern he describes is not a lack of preparation. It is that one weak round, in one loop, at one of several companies, is now enough to end the whole thing.