I don't want to pay the cost of Machado as a rental, and I don't believe any player who says they might sign, just look at Tavares and the Islanders, told them he didn't want to be traded last year, might resign and now they're left with nothing.
Philadelphia is not a prime destination for high profile free agents in any sport, and money doesn't really make these decisions because there are always 3 or 4 teams that can pay top dollar (unless you want to make a stupid overpay).
It's much easier for Philadelphia teams to grow their own, then resign them after they develop a taste for playing here. And I think it develops more cohesive teams, more loyalty and continuity.
Some patience is required with the current team, Kingery, Crawford have upside, Franco may be coming around, at some point Alfaro may learn how to use his elite tools, and Knapp is learning to hit. Williams seems to have turned the corner. One good reason to stick with these kids is the current coaches seem to have a good feel for teaching them how to work a count and get pitches to hit.
Given the young pitchers in the pipeline, De Los Santos, Anderson, Kilome, Medina, Sanchez, Romero, etc. pitching should continue to improve the next few years. So they just need a good, but not great, offensive team.