Well, you and I might have differences with what constitutes a 'long time' (though admittedly time always seemed longer when watching VV battle through another down phase). Moore lasted three starts coming out of spring training (9.82 ERA) before being sidelined with injury. After a stint in the bullpen, he made six more starts in late-June/July (faring better with a 5.60).
Anderson made eight starts through April and May (6.96) before himself being shelved with injury. He didn't appear again until the end of July, DFA'd after three relief appearances.
Velasquez had the best go-of-it, at least until he hit the wall again in mid-June. In 13 starts beginning in late-April he posted a 3.90 ERA. In the five games after, 12.23.
I don't know what constitutes a long time, but Moore and Anderson combined for only 17 starts. Velasquez of course had more, but performed better and was a known commodity (i.e., ride the wave until it crashes).
I definitely agree that the primary issue was (is) the club's lack of depth. With Suarez and Falter the only real farm-sourced SP options this year, the Phillies were further pinned when injuries kept Suarez in the pen and Falter - well, you know. That said, while I might quibble over whether the performances of Anderson and Moore fit 'normal' for 4/5 starters, if the lack of organizational depth pushed them from 5/6/7 level into that of 4/5, I guess it could become a bit more acceptable... only not.