Darvish is a much better idea but there's simply no indication the Phillies are in on him, or he's interested in them, and certainly not any indication that they could structure a more team-friendly deal that he'd want to take over another offer. If he settles for less in any way (contract-wise or by joining a less certain contender) it will be to go back to one of his previous teams.
It is of course entirely possible that the Phillies aren't bluffing here, and that they simply do not like any of those Top 4 available FA pitchers at four years or more, and they will happily settle for a lesser guy and the kids. They could still give a lefty three years or get a one-year guy, and if this really is a 78-81 win team, they'll have a lot of options in July.
But I also think the state of the market is something the Phillies could take advantage of. If the Yankees and Dodgers are sitting out to reset and teams in general aren't hot to spend, the Phillies can do so without little consequence. But if their analytics are telling them the same thing as other teams, it's not an easy call either.