As i said it is difficult to judge how difficult it is for others when it is easy for yourself.I also doubt this is true. When I first encountered GT1 and 2 I was just doing arcade racers, and I found the licences frustratingly difficult, so I never got into those games. Now I can get gold on the first or second try, but I've unlearned how to drive NFS, Burnout, etc. The more arcade racers they can coerce away from the dark side, the more successful the title becomes.
However, I do agree there should be some sort of difficulty slider that can be moved all the way up to literally "impossible."
But if you look how little threads we have about difficult to do gold medals it is a hint on how easy they are.
And most of those threads are from people that have not understood that you don't have to finish 1st in some tests/mission to get gold and it is wiser to let faster cars pass and use their slipstream instead of blocking them and then complain about how stupid AI is for ramming them...