I've played for about 24 years. I'm very interested in how this works out. I think quality of practice is very important as well as time spent. I'm certainly not going to dismiss Rocksmith it may get beginners to a level they can go on from, it may be a good practice tool for veterans.
I will always remember one night putting a clock next to me and did 45 mins of constant finger picking exercise no breaks v intense. After that I felt fluent with right hand technique. Those 45 mins were more important than many of my 5-6 hour sessions.