This has been explained in the past by AOP, defining p2w to p2p.
I cannot find this post right now so I'll try to re-explain it quickly.
f2p has an item called Miraculous Ark. This is ONLY available from the boutique - buyable with BC/real money.
It's considered a p2w item because you buy time.
Anything p2w considered is paying real money to win time you'd have lost if you farmed whatever you'd farm for.
Because p2p is all but p2w, based on fair and equal to everyone with no real life interferences, there is no way to "buy" yourself time to reach endgame.
If this makes sense to you