I would the main driver was economics. It would be easier and cheaper to manufacture one big screen in the middle compared to a bunch of physical controls with wiring.
Also makes it easier to change things later in the design if you do not have a bunch of physical controls to move.
Do not forget the massive "tablets are the future of computing" hype because Apple released a thing. Touchscreens were super cool by association. It was all pretty stupid. I say that as someone who creates mostly software for touchscreens... using keyboard and mouse because they are much better input devices. You just need the space and the budget for them.
Also makes it easier to change things later in the design if you do not have a bunch of physical controls to move.