I just did some rough calculations on how much it would cost to make it to shodan in three different dojos I have trained in. Using the required hours to test schemes (anywhere from 600-900 hrs), and adding in testing fees (nominal fees really, like $30-$35 per test, shodan is in the hundreds usually), annual Aikikai dues, etc. and it comes out to approx. $5000.00 in 5-6 years.
Now that IS a lot for a hobbie, but it's NOT a lot for an educational course of any kind. You pay much more than that per year of University. I paid $10,000 grand for my cheesy technical diploma (Computer Programming) course, which only lasted 10 months.
Even if sensei had 30 regular students that paid all dues per year, that is only like $27,000 per year (I think that is the poverty level here in Calgary).
I still don't like having rank tied to money, but I think I'll shut up now as far as the amount is concerned. With that kind of income our sensei's still HAVE to have another job!