I feel like this is disagrees with stuff like ICv2, where there were only one stretch where Pathfinder wasn't second to D&D on the chart: when Starfinder released and when PF2 was announced. Since PF2 released, it's still in its second place position while everything beneath it shuffles up and down. Heck, even Cyberpunk didn't manage to top it even with its video game coming out.
Here’s an interesting quote on this topic yesterday from a Paizo employee:
“Paizo never has and never will surpass D&D when WotC is actually trying. Even the window during which Pathfinder was the #1 RPG on icv2 happened during the timeframe where WotC had already announced 5E, was winding down 4E, and was in the middle of restructuring their distribution network to start doing direct distribution to Amazon.
PF2 reaching even a fraction of the sales of 5E can still be a wild, mind-blowing success because 5E has the benefit of 50 years of name recognition and a multi-billion-dollar division of the most powerful toy company in the world backing it. Paizo is still barely more than a mom & pop shop transitioning into its second generation of leadership, with less than a hundred employees and exactly one leased physical location that houses all of the offices, server room(s), and warehouse for the entire company.
A 3pp company might have 1 or 2 full-time employees (who still have day jobs) and an average product sale for a well-known 3pp company is equivalent to about 2% of the people who have registered organized play characters for PFS. WotC is as much larger in scope than Paizo as Paizo is larger than one of those 3pps. And just like how a 3pp can be successful with a tiny fraction of the sales that Paizo has, Paizo can be successful with a fraction of the sales that WotC has, because the size of the market is so large and the scope of the two are so different that any direct comparison misses the point.
D&D and MtG combined make more money than Transformers, Power Rangers, My Little Pony, and Monopoly combined, as was revealed in recent shake-ups following WotC's last earnings call. That's ridiculous. That means that 5E isn't just a juggernaut in the market, it is now the engine that generates the market that every other game exists within. And that's not unusual, D&D has long been the centerpiece of the TTRPG world and is really the thing that opened the door for everything that's come since.
PF2 has been consistently blowing past benchmarks established by PF1 and Starfinder, which themselves were record-setting product lines for Paizo. That's really the only metric of success that's truly relevant, and outselling every product line the company produced prior to it at unheard of speeds definitely checks that "success" box.”
(Link: paizo.com - Forums / Pathfinder Second Edition: General Discussion: Paizo/Pathfinder 2e and the Current Market)
Now this isn’t data, it’s just a comment by an employee (and not one who’s in charge of financials). But still, it’s interesting to hear how things look from someone “on the inside”, both with respect to their size and ambitions relative to D&D, and the comparison between PF1/SF and PF2 sales.