Borderlands 3 was a brand new game in a well established franchise with its previous installments available on PC, meanwhile Sony's games are multiple years old and since Sony had no prior history on PC there's no established PC playerbase interested in those games. Overall I think $200mil for 4-6 games was a decent offer.
You have to see it from Sony's side:
- it would be "minimum guarantee" money, NOT 200 million on top of unit sales. Epic would take all unit sales until the 200 million are fulfilled.
- Sony probably doesn't want the narrative that they can't make 200 million with the strength of their franchises
- if Sony wants to build up a presence and audience on PC, making it exclusive (for x amount of time) on a controversial and unsuccessful storefront is not the best path to take.
- regardless of age, I think sony IS of the mindset that their games are more prestigious and better than Borderlands 3 and deserve better payment