Profit is revenue minus expenses. Expenses are a lot of things, from salaries to game development, to next gen hardware investment, etc.
Lets do this another way.
This is operating income for Sony's game business by fiscal year, 1995-2010. You can actually see the years Sony took big hits in next gen hardware development, in 1995, 2000, and 2006.
Note that the peak of the PS2 era Sony maxed out at 113 Billion yen, with the 2000-2005 period racking up about 265 million yen.
Now, look at 2014 to present:
2018 alone was a 190 billion yen operating profit. 2017 was about 170. 2016 was about 130. In two years the PS4 earned Sony far more operating profit than the PS2 did over its entire lifespan, despite the PS2 selling substantially more hardware and software.
The cut that Sony gets from a third party game is about the same whether its sold on a digital storefront or via retail. So that being the case, why is sony profit completely destroying all records right now? Why was the profitability of the entire PS2 catalogue nowhere close to what was brought in over two years on PS4?