I agree with your points.
Everything said before regarding the market of gaming I also agree with. Costs grew, consoles became a monster (along with their requirements that essentially simplify the PC version) and as such, what sells the most is what gets made, the other suffers. You have to maximize the sales etc...
I personally believe that Dragon Age Origins was a significant point in gaming history regarding this topic. It seemed to be the last best effort of a major studio to not only attempt to pacify the era by combining the two but also to hold up the old as a style not to be forgotten AND incredibly fun in both modes. It was really well done. At a time when the studio was being bought out by EA and all previously mentioned points took hold.
It was an effort that I hold up as a beacon of light that Obsidian seems to have begun to take the reigns of.
As far as i'm concerned, Bioware succeeded until the "trend" and changes took hold that rendered DA2 and DAI for us. DAI being a game that seems to not know what it wants to be (a Skyrim type open world game that by the way no one can compete with *see note* or a game that embodies what DAO succeeded in being and failing horribly).
DAO combined the 3D first person with the isometric IE "feel" extremely well. A very good balance that was thrown away up through DAI.
As far as 3D being what everyone wants, it is only a section of gaming. ARPG's thrive on this style. It is viable in PC gaming so the argument puzzles me.
Thank God that someone is there to showcase it.
It may not make the most in terms of sales, but it certainly is profitable. Just not to the point where large publishers want and I think that is the issue. Although I understand that it's a business, it's just gotten ruthless.
NOTE: You either develop an open world RPG or a focused RPG. Pick a road and go unless you are committed to delivering both. Bethesda knows their game and their vision. They hold on to it and it shows. ES6 will either showcase this or seal the deal.