I agree with everything you've said in your post. I've started training with a 7th dan aikikai shihan these past 2 weeks. From 3 hours/week, I've upped my training to 9 hours as my life circumstance allows me to. Hopefully, I'll see some improvement. Agree also that it not the amount of hours but also correct practice. How to do "correct practice" this maybe for a different thread. But right now, I'm focussing on keen observation on the shihan, full awareness of my every move and honest assessment of my weaknesses. The 3 things above also maybe for a different thread again.
George S. Ledyard
It is important to "get out" and train with people from outside your immediate circle. Set styles or slavish devotion to a single teacher seldom produces anything really top level, although it might produce a good "stylist".
Does watching a lot of youtube videos count?
Seriously, I'm not a big fan of attending seminars as they are expensive so I watch videos of different shihans (my fav is Endo sensei, also Yamada Tissier, Osawa and Chiba sensei). I try to understand what they're imparting (verbal and in their movement) and try to mimic the movements. It's like you attended seminars for free...and can replay them over and over.
But I also understand that you also need to experience first-hand the techniques of the masters to gain greater knowledge of how techniques are really done, but its not everyday you get to be their uke anyway.