Yeah, there has always been bleed off from D&D to other games. it is the tide that lifts all boats. PF2 appeals to D&D players that want more structure and crunchy bits, plus their adventures tend to get high praise and Golarion is a cool, diverse setting.You'd think that, but PF2 has grown the playerbase. Paizo selling more than ever. I think they owe a good deal of that to the explosion of 5E and community overall growth than any secret PF2 sauce.
I am honestly pretty dismissive of PF1 grognards who accuse Paizo of abandoning them or whatever, especially when they make questionable claims about how PF2 is dying etc... Paizo gave them 10 years of solid support, but it was time for a new edition. If there was still that big of a market for PF 1E material, some company would be serving it via the OGL.