Nice post Dave de Vos.
I think you are spot on with your assessment. Showing up and "clocking in" doesn't really do it either though. I've trained with several Aikidoists who have been doing Aikido since the 70's, most of them show up regularly, bow in and "train" several times a week. But, while they are physically there, they are not mentally/spiritually there, so they've stopped growing. They have 30+ years in class, an honest 10,000+ years "training" but they were only truly present for 2000-3000 hours of training. While some Uchi-deshi who has been training for only 1 year could easily rack up 1500 hours of very intense, dedicated training.
In most of the Martial arts I've studied I was in the lead pack of students. Those that gave 100% to everything they did, living breathing and eating the training. However I have done a few martial arts where I noticed that I was not there, I just was not as interested in the training. Even though I had the same "time-in" in two different systems, the one's I cared about I became very good at very quickly, but the ones where I tried less I was never in the lead pack of students.
You have to be present in order to improve. That gets harder the longer you study one thing because you must continue to stay interested, finding new ways to improve and develop. Most hobbyists will never do this, so they brag about their 30+ years of training, but really have done less then a serious 3 year student.