The 4m number is just a guess based on some info their studios have shared on their games.
Two days ago Rare shared that they have reached 8.4 million SoT players and that 2m of those are new players when they launched their big year one update back in march. Back in April Rare also shared that the split between gamepass and game ownership for SoT is 50/50 so 4.2m own and 4.2m use gamepass.
Forza Horizon 4 devs also shared yesterday that their game reached 10m players. Forza Horizon is more popular so it probably sold more (maybe 5-6m) so it's possible than 4m used gamepass on that game.
THanks for the data, but we can't confuse people that made a trial sub or month sub to test/play one game with recurrent/permanent subs. But sure it is a good start, much better than what PS+ currently have (price is attractive if you like the games offered).
duduspace11 "Well, since we are estimating costs, Pokemon Red/Blue did cost Nintendo about $50m to make back in 1996"
Mr Puggsly: "Hehe, I said good profit. You said big profit. Frankly, not losing money is what I meant by good. Don't get hung up on semantics"
Azzanation: "PS5 wouldn't sold out at launch without scalpers."