"Sold a million" might be something cool in music, where you get a "platinum" for selling a million of CDs but a PS2 full price game was $50, of which ~$10 went to Sony for license and $10 went to various expenses from shipping to shelf space. So "sold a million" means, at the very best, $30M in the bank. When you spent $40M to get the game out it's not a very good number to have in the bank (it's a nice chunk of change if you spent $2-10M like other AAA devs at that time). And it's unlikely Killzone ever sold a million at full price to begin with.
Sequels and Horizon or whatever else you like are irrelevant to the financials. Sony game business does not seem to be doing well now but how is it related to the financial performance of an European studio from 20 years ago? (Even though I can see how acquisition of Guerrilla eventually led to the current sad state of affairs, the Guerrilla's boss had been in charge of Sony's first party development during the period of Sony's decline).
Sequels and Horizon or whatever else you like are irrelevant to the financials. Sony game business does not seem to be doing well now but how is it related to the financial performance of an European studio from 20 years ago? (Even though I can see how acquisition of Guerrilla eventually led to the current sad state of affairs, the Guerrilla's boss had been in charge of Sony's first party development during the period of Sony's decline).