Um Marlan, it’s already been done!
EA Sports has a line of video games Sports Active for Nintendo Wii the latest exergames offering a virtual personal trainer and fitness programs that include a variety of cardio and strength exercises.
I unfortunately do see this happening in the future. I see it with these 24/7 gyms which now have FlexTech a retrofit digital trainer. The exerciser inserts the USB flash-drive into an exercise machine which displays the scheduled exercise to be performed and how to perform. No need for a trainer! Scary isn’t it???