It's only 1 million in 5 years
Any they had it out super early, and didn't push it as hard. It was more or less a side thing to offer PS3 games since BC was not an option on PS4. Their prices were way too high for a while, but then they added PS4 downloads. Even then they didn't advertise it well.
So they literally got 300k paid subs in a short span when they dropped the price and actually advertised the service.
Imagine if they rebrand/re-launch for PS5 which they will do. Your going to see even more "paid" subs. Sony has the stronger brand in their games than Microsoft at the moment.
The thing Microsoft has that Sony doesn't is local Third party games and older last gen games that can be played locally. Which is a big deal in my opinion. Even so, MS has basically been giving the service away for a long time. And been giving their sales away with the idea that the subs will offset the loss in the long run.
Which is a huge gamble if your brand of games are not bringing much excitement to begin with.
Time will tell honestly for both. But the one thing Sony has is the games that are more sought after. If they make deals for Japanese third party support on the service for locally downloaded PS4/PS5 games.
It's going to really heat things up for a lot of regions.