I actually wonder if somewhere between making the decision to turn into a man for fame and money, Satomi was hoping that the MC was never going to find another girl and when her baseball career was over ( in her mid 30s) she would turn back into a woman and get with the MC.
In some ways that would feel as a Romantic ending but in some ways it would make the MC seem very useless in that in a world full of men, women and everything in-between (literally) he couldn't find one partner.