In large measure because he wants a competitive team beyond the next two seasons and also because he doesn't know what the cap details in new CBA will be -- I'm expecting any hard cap to not be less than what the Dodgers are committed to now, but who knows what will actually happen?
Just as everyone talks about wanting a balanced federal budget, I'm guessing all the talk of a hard cap to increase competition will be at high enough $ not to actually do much to balance competition. Who really wants it? They likely take action on things like deferred payments and create a new cap above the current lux tier, which is high enough not to be a severe hindrance to anyone. Suggest a hard cap at what the Phillies currently spend and the higher spending teams will want that to be accompanied by either a significant reduction in lux tax rates and/or a required minimum salary spend which is a lot higher than what the 'poor' teams now spend. The players will want none of this, excepting the floor on team payroll.
MLB took in well over $350 million in lux tax last season and certainly more for the coming season. Half goes to the players and half to the 'poor' teams. I couldn't find $ received by individual 'poor; teams, as it seems deliberately opaque, but if we assume it went almost entirely to 5 teams, that would be close to $35 mill per team. The owners of those teams are not poor and the value of their teams has appreciated. I suspect they would rather pocket those $ than have the wealthy teams forced into a smaller salary budget.