This may seem simple at first, but if it ever comes true, it will be in the somewhat distant future, considering where PP is currently and where Bitcoin is. It is still much easier for the average user to pay with PP, and in addition, he has guaranteed protection that he will get what he paid for, or he will get his money back.
The protection of the buyer who would pay directly with BTC does not actually exist, and here again we have to rely on payment processors who again in some way actually play the role of an intermediary and can be a problem if they require KYC or refuse the transaction for the reason that the coins are not clean.
If PP and similar companies were to cease to exist for some reason, the market would certainly look for an alternative, but with all these so-called stablecoins and CBDC, it somehow does not seem to me that Bitcoin will be the first choice.