The best way not to contend is to try to contend.
That is, forcing things by truncating the rebuild by trading young assets and signing big free agents is how a lot of teams remain mediocre indefinitely - they get an instant boost and maybe get over .500, then find themselves with an aging team, little salary cap room and a depleted talent pipeline. Oh, we've been there and done that?
Phillies are now in talent consolidation mode, that is, they've rebuild the farm system, they've accumulated quantity, now they have to develop it, and accumulate ML caliber quality. Until you hit "critical mass," major signings and trades are counterproductive, because they may preclude future options (especially now that there's a "hard" salary cap due to much higher penalties for overspending).
It's frustrating, but I'd much rather they do it the right way and build a team that can contend indefinitely than a one or two year "flash in the pan."
Klentak made it pretty plain that he has the green light to spend, and I think the $40M or so they've spent already (cutting Harrison, Hellickson QO, Benoit, Kendrick, etc) suggests it's not budget constraints but strategy that precludes a big FA signing this year.