If they aren't pulling in enough money for a AAA developer to continue making games with the rising costs of development, then they pretty much have to change what they are by necessity.
Traditional RPGs found themselves a niche genre in an industry that was having the cost of making games constantly going up while the price of buying them wasn't changing. They weren't winning people over, and the core fans weren't deemed enough to sustain development of future games.
There was little reason for costs to be going up. If BioWare, after KotOR, had pivoted to become an independent developer who distributed their own games digitally (through the infrastructure of the BioWare store that they had already set up for NWN), they could have published DAO themselves and not needed traditional publishers.
I actually suggested it at the time. And then Valve basically did the same thing when they started Steam.
Steam shows us that smaller studios can produce and sell high quality small market games. But BioWare went a different direction, first fully voicing the NPCs (something to which I objected when they first did it in 2003), and then adding cinematics.
Cinematics and voice acting are incredibly expensive, and add nothing at all to the game. Nothing about the gameplay changes at all with the addition of non-interactive content.
While Origins sold rather well they also changed quite a bit by streamlining a lot of stuff compared to Baldur's Gate, to the point where many traditional RPG fans complained about the "dumbing down" of the system.
Granted. At the time, I described DAO as my compromise position. I would compromise that far, but no further.
I hold to that.
Not long before that, Bethesda also decided they needed to make some changes in order to keep Elder Scrolls going as a series and so Oblivion also streamlined things.
The action combat kept me from following TES that closely.
To many people, those games had already stopped being what they were. Both Oblivion as an Elder Scrolls game and Origins as a spiritual successor to Baldur's Gate.
DAO was never the successor to Baldur's Gate. If anything, it was the successor to Baldur's Gate 2, a very different game.
DAI is the successor to Baldur's Gate.