I think you are missing the point. New users often do not even get a 19 year old star potential player. My point is I think to make things easier for new users that they be given a player of a max age, min potential and min skills to ensure they get a at least one player worth training.
I don't disagree there. I am fairly certain that my best starting player with my main club was an 18 year old starter potential guy. I just think that what is defined as "worth training" is grossly inaccurate.
I have seen other people advise new users they know to let their team go bot and try again to get a better trainee. Not sure that is a real option but it does make a point.
Which is precisely why I try to let people know that it's okay to not have an elite trainee when you're starting out. There are plenty of purveyors of the conventional "wisdom" about how these players are fairly useless (or, as you claimed, even allstar potential players are "depth players at best in decent leagues"). Just because something is echoed by a thousand voices doesn't make it any less wrong. People who feel that they need to wait until they have an advantage (either because of superior starting trainees, tanking to build up to afford ridiculous salaries, etc.) to play the game are simply advertising to the rest of the game that they know they're not good enough managers to compete on even footing.