FYI, PoE2 has passed 1 million in sales. PoE1 and P:Km are about 2 million. And The Outer Worlds is at 3 million. These are actual numbers, publicly mentioned in some form or another by their respective devs/publishers, not Steamspy b.s.
PoE2 made it past 1 million? That's news to me. The way most people talked about it, you'd think it failed completely. Well, relative to its budget, it probably did, Obsidian seems to behave like it performed way under expectations. A good chunk of its sales were probably long after release through sales.
Apparently it picked up after 2019, but a year after release it had sold only around 100K copies. That can answer those who are comparing BG3 and Solasta's sales, a marketing budget goes a long way. We can say PoE was a known brand when PoE2 came out and it bombed hard due to no advertising.