But the luxury tax limit isn't what the Phillies are up against. They intend to cut total payroll compared to last year. The cut might not be as drastic as we feared, or as drastic as the team intended prior to Dombrowski. But it's still going to happen.
They are at $179.5 million now. I believe andyb predicted the final number will be around $195, but they might have to go higher if Didi gets $15 million. They won't go much higher though. And that first number doesn't include any major league salaries from minor league deal guys, or small additions (bench player, cheap reliever).
What's more, even if they are willing to spend to the CBT threshold, they still can't do it in the off-season if they aren't going to be willing to exceed it in July.
If they sign Didi they probably aren't signing a significant starter or a second significant reliever. Unless they can unload Segura, or move Velasquez to free up a few bucks.
The market for Didi might not be as as good as we think though. The Reds are no more likely than the Phillies to bid big. And apparently his analytics aren't that great (defense isn't as good as the eye test, exit velocity suggests an offensive decline is coming) which tends to lead to uniform valuation. He might have to settle for something close to Simmons, especially if he wants a second year.
It's true that if Villar can play defense and is a little less awful offensively than he was last year, you could at least spend that money on pitching or an OF bat.