Ca. 5years to lvl 30 is a joke
On Rafa's example on a 22 race league with one race per week and a week off (this being about the longest plan for a seasen that I could think of) it would take 4 years to get from level 1 - level 30.
If your season were 15 days, it would take about 1 year, 5 months, and 26 days to reach level 30. So, still no where near the 5 years that you state.
Maybe that is a bit long. And maybe we do need to accelerate getting through the first ten to fifteen levels, but that is a developer decision.
This is the reason people quit, the grind is ridiculously long