The Phillies wealth isn't infinite. If they spend $24MM on Burnett that money doesn't magically return once he's departed. The team is flush, no doubt, but with the way they have performed the last couple of years CBP isn't exactly the mint anymore. As I've said several times this offseason, instead of wasting money on washed up mediocrity (Chooch Ruiz/Byrd) and old pitchers (Burnett) why not invest it your player development system or international operations? Or just save it for a rainy day? (Or just sign good players).
You are right: Burnett does not 'hurt' Philly, but his contract is an unequivocal waste of resources as are virtually all of Amaro's moves.
Save it for a rainy day? I'm fairly certain if teams have a set payroll budget but spend X amount of dollars under that they get it keep it for future seasons. If you have money to spend on that season then spend it. And you are right the Phillies are on a down turn. All the more reason to get as many wins as possible with a new television contract coming up after this season. The Phillies will spend the same on player development and international operations whether a deal like this was made or not. Just like almost every other team. The Phillies may not have infinite money but they have a lot and will get a lot more after this year.