Doflamingo is content in jail cracking up and reading the news. He fears Kaido because of the failure, so he's frankly better off there.
So you... lmao. You post a scan where they even say that just subduing Kaido hasn't impeded him. Nothing done to this man has stopped him from conquering and maintaining Wano. The whole point here is to make sure he doesn't just do it all over again. Oh but I'm just saying that, what does Oda say? Surely he's not perseverating on the idea through his characters