Haha... Fantastic. No wonder Shino was always so focused on Naoya's behavior, only making casual comments toward Saki along the lines of "you're being dumb!".
Honestly, if this was a total wish fulfillment manga instead of a bit of a meta-commentary, we'd see Naoya win the lottery. Because I think the single biggest reason two-timing won't work in reality is indeed money. If Naoya doesn't have to worry about money, if the girls have everything they need to pursue their interests and hobbies and enjoy themselves, they'll be so much less stressed and less likely to blame the two-timing itself for their problems (whatever they may be) in the future.
Anyway, a serious girl like Shino definitely has synergy with Naoya, so I'm rooting for her! According to the "five colors" theory, I guess there's one girl left...