If they did they would lose almost all advertisers and face strikes from the employees. The MSM would rather go out of business than allow a conservative media outlet to exist
Maybe lose all their current advertisers, but get a whole bunch of new ones. It would be the “Rush Limbaugh effect”, otherwise known as “nothing succeeds like success”.
If they sell a lot more newspapers, the advertisers will come.
However, you are right that the Graham family that controls the company would likely never sell to a conservative.