The problem is that income levels have been allowed to go beyond what is viable, the result is that some riders are owed money by struggling promoters. The very top guys (GPs Polish league, Swedish League and even some fit in the Elite league as well) are said to be able to make many thousands per week, along with some generous sponsorship, I read it to be well over £30,000 per week for some. These days riders can make a reasonable living in the Premier League, where in the past it would have had to fit in with a regular job for many, below that there will be very few making any sizeable amount of money. I have no idea what people make in the sports you mentioned.