I apologise for thowing an idea out into the ether and not adding any body to it. So here goes.
My thinking goes something along these lines.
If a person wants to pilot a Boeing 747 ((jumbo Jet')they can not rock up to their local airport with their private pilots licence and wods of cash, hire a 747 and go out and fly it.
They have to 1st learn to fly low powered single engined aircraft and graduate though various types of aircraft to the point where they qualified to fly 'heavy metal'. My understanding is that it takes the average pilot at least 10 years of commercial flying to get to this stage. ( I know there will be/are exceptions, but this seems to be the norm.)
In the case of singing, I would suggest that to improve your accuracy of reaching musical notes and with timing, amongst other things, it would help if you learnt another musical instrument.
In both these cases, training in other related, but different areas, you aquire a broarder spectrum of knowlege and skills to help you out with your ultimate goal, be it piloting a 747, singing in your favorite genra of music, or for that matter driving a motor vehicle.
With both flying and singing you are usually sharing space and time with other users, just as motorists and cyclists (should) share the road. So if we had to graduate from the simpler through to the more complex machines we, hopefully, would learn about the inherant advantages and disadvantages of each type of road vehicle and take this into concideration when driving or riding.
Walk a mile in my shoes and maybe we would treat each other with respect.
A system like this should also only allow people to graduate to the most complex machinery that they show competence in handling.