I mean they didn’t win last-gen but they still sold about 165m consoles.
I think you're getting the PS3's numbers muddled with those of the PS2. They sold on the order of 82-85m PS3s, depending on who you ask.
I didnt watch video, but its very simple, they corrected mistakes they made with PS3, like much cheaper price point and hardware that is much easier to work witch.
Also with "big comeback" it sound like they totally failed last gen.
Maybe not sales-wise - albeit they went from selling three times the combined number of their rivals' consoles in the previous generation to spending roughly three-quarters of the generation in third place - but the console's obscene R&D costs put a major financial drain on the company. They would probably have needed PS2-type numbers to turn a profit from the project, and they fell a long way short.