You are missing how a PD programs music in a major market.They'll need a new PD to pull it off though, as the current PD historically does not touch anything remotely guitar rock unless the popularity has hit a threshold that makes it impossible to ignore (like Beggin). They would need a PD who actually would want to play guitar rock along with synthpop and indie.
First, research shows the general format area based on testing a variety of formats using small samples of, perhaps 6 to 8 hooks for each. Such a test also determines the size of the format opening and the vulnerability of stations already partially filling that space.
When the format is picked, a large list (often two to three times the envisioned library size) of potential songs is made up, often using what is played in similar or partially the same formats in other cities. A standard OMT (Online Music Test) or AMT (Auditorium Music Test) is done to find the songs that are playable.
The PD does not pick the music. The listeners do. And in a group owned situation, the decisions will be made by a team, not one individual.
Heck, even back in the mid-60's when I owned a Top 40 station, we had a panel of two men and two women, one of each gender older and one younger (within the target) to pick our adds each week. Even though I owned the station, I was not stupid enough to think I could predict all on my own the songs we should play.