There's no need for a case study on the type of buttons. It is objective, that a sensor is less reliable than a physical button. Have you ever gone to a public bathroom and struggled to use the water/soap/dryer because there is a sensor to activate them? The issue with sensors is that their location needs to be extremely precise and clearly labeled. The distance from your hand to the button needed for triggering is not clear. The lack of tactile feedback is an issue for blind users. There is no reason to scrap physical buttons - it works, there is nothing to 'fix'.
You're claiming sensors are less reliable than physical buttons, the emphasis is on you to provide evidence to support this, in 20 years of using Pendolinos with touch sensitive internal buttons, I've never known one fail in a way that wouldn't also render a door with push buttons useless.
Regarding accessibility for blind people, again, where is your supporting evidence to back up this claim? For internal doors, you can tell by touch that the door in front of you has opened and for external doors, the audible hustle alarm that sounds when the door opens is a dead giveaway...
It's a non-issue.