They made a half-hearted commitment to Rojas after initially making a more serious one. Keeping Pache over Cave, or anyone, was the insurance policy. And they certainly expected Merrifield to be more viable in a part-time role (in fact they claimed playing him less would help him thrive, in addition to him being the only player they pursued who would accept such a role).
At this point in his career Pache only has potential if he starts playing at least semi-regularly for the Phillies or gets traded. One or the other will likely happen in the next 6-8 weeks. He's just buried now because they didn't want to lose him for nothing (or at all if Rojas doesn't stick).
The details of all of this really don't matter so much, the reality is the roster just doesn't make any sense with two RHB defense-first OFs plus two RHB utility players. None of whom are hitting well enough to play LF or RF at the moment either.
It's nothing the team can't endure for another month or two, especially if the offense improves, but it's not how they'll go into the All-Star break.