The question is, how do you know WB wouldn't be okay with a variant of the status quo without the CBS shows dragging down the network? CW shows still live or die based on who's watching them on linear television. If Netflix is what's keeping the network afloat,
why not sell directly to them? Why maintain your presence in a medium where even the biggest players don't really want to be there?
Color me skeptical that an entity with absolutely zero experience in content production is going to do all that well, but Salem and Manhattan seem to be doing okay for WGN America. The problem I have is, Tribune is such a
weird anachronistic hybrid unlike anything else in television, with a bunch of news-producing CW affiliates in really big markets on par with Big Four stations, but a fairly traditional network affiliate operation everywhere else, and one single haphazardly-distributed cable network that's slowly shedding its status as the last vestige of the "superstation" era of cable television. Do even they know exactly who they are?
Depending on how bean-counter-y the people running Tribune are, I wouldn't be surprised if they decided it was worth it to ditch those big-market stations and WGN America and refocused on being a traditional network affiliate operation, and got rid of any reason for them to be in the expensive content production business. Or maybe they make a play to be a big Sinclair-esque operation, but those big-market stations mean they're running up against the market cap already. Or maybe, since cable is where all the money is these days, WGN America is the one part of the company that's non-negotiable...
As the link I posted two paragraphs ago states, I think Tribune is going in the exact wrong direction if they want to make a huge financial outlay on behalf of WGN America. Live events are the only reason for the existence of linear television, and WGNA is ditching the live events they already had in favor of a scripted-programming-centric strategy full of stuff you could just as easily get online.
By the same token, I'll be convinced that WB is interested in running down the Big Four when they make a play for live events people actually care about, and I don't think they'll ever be able to consistently compete with them on the same terms until they do, but on the sports front they're pretty much shut out until next decade unless they're willing and able to siphon sports from Turner, and the economics of the sports business are so cable-centric these days.