.....XP and leveling in GT5 is nothing but an artificial time sink designed to make the game last longer. It's bad game design to do it this way and it really hurts my enjoyment of the game.
If you want me to play the game for many hours then give me lots of interesting and challenging events to complete, don't artificially restrict what I can and cannot do with a level system.
I'm afraid that I have to agree with this.
It does seem an artificial time sink.👎
The XP leveling system does seem poorly thought out. I think the problem we are having is that for the most part, we can beat the early races without much of a struggle once we have an appropriate car. We therefore want to try the higher level races since we expect that they will be harder and more of a challenge. However, we then find that the XP leveling system prevents us from racing in the next higher event.

So we are forced to repeat and repeat races that we have already beaten, just to earn more XP pts to get to the next event.
In my opinion, the problem is two-fold:
1) Most of the early races are too easy
2) The XP point differential between the levels is too great
The first problem could be solved with more events, (YES PLEASE!), or maybe HP restrictions on the individual events to prevent us from using cars that monster the events.
The second problem could be solved with a simple adjustment to the XP level system. For example, since we earn approximately 7900 XP pts for completing all the Beginner Series races, then 7900 points should be the point at which level 5 would get unlocked. And since we can earn approximately 13000 XP points for completing all the Amateur Series races, then 20900 points should be the point at which level 10 would get unlocked. And since we earn approximately 30100 XP pts for completing all the Professional Series, then 51000 XP points should be the point at which level 15 would get unlocked. And since we earn approximately 100000 XP pts for completing all the Expert Series, then 151000 XP points should be the point at which level 20 would get unlocked, etc.
A further wrinkle that I would like to see in the XP point system is that the amount of XP pts earned in a race would depend upon how strong your car is. Winning a Beginner Series race with the Minolta Toyota should not earn you the same amount of XP points as beating the same race with Daihatsu Midget D-Type.
Respectfully,
GTsail