I said "a decent chance that's as good as buying the thing". If these mega companies stick around and continue to offer access to the content, then it is as good as buying it (arguably better if you don't have to store it and can download onto many devices over decades). But note that this was all preceded by "a decent chance". There is also a chance that it won't turn out to be as good as buying, if the company goes under, gets out of that line of business, or loses access to the relevant rights.

One important question, which I don't know the answer to, is whether Sony is nuking stuff from your devices. If not, then they could claim that you bought the thing and can keep using it on your existing devices. If you can move the content from a PS5 to a PS6 in 5 years, then arguably it's fine to say you "bought" it. But if they're wiping the content from your local devices, then you've definitely not bought the thing.