We thought the deal was good for Oden because he could save Wano's citizens just by dancing. In reality, it was even better for the Beast Pirates to keep Oden at bay for 5 years!
I don't know if they significantly grew in strength (doubtful because they mention Moria greatly damaged his forces) or the Beast Pirates + Orochi simply didn't want to face the entirety of Wano who would no doubt back the rightful heir Oden in all of this. Brilliant move by Orochi to insert a condition of having Oden shame himself in the capital for all of Wano to see every week. People lost their trust and respect of Oden, there was no way armies of samurai would be willing to back him after 5 years of this.
I wouldn't surprise me if Oden got some very favorable terms to keep the dancing going. We didn't hear about a single Wano innocent being executed during that period. The deal was broken only when Orochi and Kaido finally felt they could overcome Oden, his men, and nobody else in Wano would rush to their support.