So aikido should take at least 30000 hours? 10000 for gotai, 10000 for jutai and 10000 for ki no nagare? Not to mention that your still "just" doing kihon waza in different forms. Another 10000 to learn jiyuwaza and 10000 for randori?
What do you define as the difference between ryu tai and ki no nagare? (I understand them as both being used to describe flowing waza).
Malcolm Gladwells book "Outliers" suggests 10,000 hours of practice for true mastery. O' Sensei dedicated his life to the martial arts. That is the dedication, which is needed and it needs to be accompanied by the spiritual purity.
In terms of practice we always used to do concentrate on kotai them move to jutai followed by ryu tai (which would hopefully develop to ki no nagare with time and practice).