This site says that 50 man is the very highest end of the market in Tokyo:
https://bossgoo.sakura.ne.jp/sugardaddy-souba/
IMO, nobody is paying 50 man a month for one woman who is not their wife, unless they are a company president or celebrity type making enough money to essentially have their pick of tight-bodied college students. Which means you need to be a competitive tight-bodied college student in order to make that much.
I think most of the steady SBs are getting more like 15-25 man a month, which is more realistically in the budget of upper middle class men (company managers, lawyers, accountants, etc.) and is roughly equivalent to the cost of doing P4P every week.
Also keep in mind that there is a sort of "innocence premium" in sugaring... girls who look young and inexperienced are more competitive. You might think that guys want a total bombshell who is great at sex, but this can actually be a turn-off for a SD.