The parallels to 2012 are concerning, but it's not a perfect comparison. Both the 2012 and 2025 teams were old, but the 2012 team was older. Only two players of note on that team were under 30, Hamels and Pence (who was traded during the season). The 2025 team had Bohm, Stott, Marsh, Sanchez, Luzardo, and Duran all in the age 27-28 range. Plus, the current Phillies have a little more on the farm (Painter, Crawford, Miller). The 2012 team had basically Domonic Brown.
Generally, though, the free agent market isn't going to make them much younger. The window isn't open for much longer, and more long term contracts will make it harder to compete in a couple of years.