XCOMs made turn-based combat cool again. Look at amount of Turn-Based games being released since then and bought, and compare it to RT. It is a simply more savy more to appeal to Divinity fans, then BG fans - it is already audience attached to Larian, and seems to have overall wider appeal sales wise. As to polls made on a forum such as this - I imagine a big chunk of people are vocal about BG3 because they care about BG IP - it will not be representetive of a wider public.
There are valid points to be made for TB combat, whenever it is to your personal tastes or not. Using roll based Turn-Based system and making it real time (as did BG1&2) does create a host of problems.
What's more, BG1&2 were singleplayer games with optional coop, while Larian games are multiplayer games first. Using TB system is a handy solution to many struggles RTwP game had, and would have.
That's not to say, that RTwP shouldn't be made - but games like Pillars or Pathfinder are archaic, and have limited appeal. I am a fan, but I know how to deal with the system. What RTwP needs is a dev who believes in the system (which curiously isn't Obsidian, as Josh S. expressed his preference of TB over RTwP) and who will innovate on the idea and bring it to the XXth century. Larian doing RTwP because fans want it, but they don't believe in it, is not a good idea.
Something I really liked about BG3 demo, is how punchy the combat feels. D:OSs (especially 2nd one) could feel grindy, with inflated health pools. They also visually communicate rolls really well (loved the critical hit dice thing) - I think this kind of presentation is really helpful. There a thick barrier to fight through when playing BG or Pathfinder or BG - the game is happening in a small text box in the corner, and not actually on the battlefield you are staring at. I believe that amount of players who really engage with the systems in those games is fairly small.
BG3 moves those things into spotlight - smart and beneficial move.
Firaxis did make TB palatable for me. So I definitely agree that XCOM did the magic.