That's the thing SIXAXIS & Wiimote was IMU controls as standard input for a console at it's Infancy , someone made a motion controller ( Le Stick ) in 1981 to emulate the old Joystick controls that was the standard in the Atari days but that was a 3rd party & no games was made for it it was just emulating digital joystick movements with a motion controller. so from 1981 to 2006 before a console used it as a standard impute vs dpad that replaced the joystick only a few years after it was introduced & was the standard on NES , SMS & so on & continued to be a standard on console games every since then the analog thumb stick made it's way into a standard controller in 1999 with the Dreamcast ( Calm down I know about the Dual Analog & The N64 thumb stick but Dual Analog /Dual Shock was introduced years after the PS1 was released & N64 thumb stick was digital much like the Joystick ) You also have controls like trackballs that was used over the years but have never been used as standard as a console's input , all of these controller inputs was experimented with in the 70's & early 80's dpad & analog sticks wasn't perfect the 1st few goes but they became standards & they kept using them until they came close enough to being perfect so you have to give IMU/ 3D mouse controls this same room to grow & not just say "it didn't work the 1st time so it's never going to work" Xbox was still having trouble getting the d'pad right even 20+ years after it was introduced as a standard , IMU controls are pretty much 2nd nature now in games & will be even better next generation Sony/Nintendo would be fools not to continue improving upon these controls now. Look how good voice commends work now with Alexa & Google Home but just a few years ago it was terrible on phones & so on but they didn't give up on it & now anyone can use voice commends.
Funny thing is that due to discouraging MS might skip out on making a next generation Kinect & Sony might slip in a cheap PlayStation camera that perfect full body motion controls.
