The problem of just looking at these numbers is that without knowing the development + marketing costs, it's all pretty meaningless. I don't know how much Days Gone cost to make or market, but if it meant that the margin was really low, then it makes perfect sense as to why there's no desire to continue the franchise. Seeing that it made $100m on PSN tells you nothing in and of itself - you need that extra piece of the puzzle, and we don't.
What I find particularly interesting from this though is how the number of people downloading feels quite low, even for some of the biggest games on there, given the impression that digital (certainly since covid) has overtaken physical by quite a lot in some regions. It may have changed now, but not having a single PSN title crack 10m is surprising to me for those games which are cross-gen (so had a combined PlayStation user base of what, 100m+ PS4s and, say 30m+ PS5s as at June last year).
Those download numbers would also be another metric to look at beyond cold, hard cash to gauge your game's potential baseline reach and appetite for a sequel too. Not that I think for a second they assume everybody who buys the first game would want a sequel - but they almost certainly do use those numbers in some way (with various assumptions and weightings) to help decision-making.
Anyway, my own particular never-to-be-fulfilled wish would be for The Order 1886 to have continued, but, yeah. <sad face>