The thing is that the goal should be winning championships, not being a pretty good also-ran. John Wall and Bradley Beal are already on max contracts and teams generally can't carry more than three without seriously hurting their depth. Committing those resources to Otto Porter pretty much assures us that the core of Wall-Beal-Porter is what we're betting a championship run on. I don't think that gets you close with the Warriors and Cavs to contend with.
what is the alternative, the closest that they've come to assembling a championship team was clearing space for a guy who wouldn't even give them a sit down. Heyward certainly didn't bother considering us- is there a marquee free agent that I'm forgetting who we have a shot at? As long as beal and wall are here, there's no shot at the kind of draft pick that can vault them, they didn't have assets to deal to get a paul George or a jimmy buttler.