Yeah, anecdotally I would agree that the first-time-around effect is real. But if it is, that also means it does not affect the Phillies any more than any other team. Unless they have the bad luck to face more of those pitchers over a particular season or time period.
Of course there is also a big difference between a good team/playoff contender calling up its top prospect in the middle of the wild card race vs. a bad team starting to give its youngsters - even fringe youngsters - a look after they've given up on a season (and/or traded their better veterans).
And then there is what I remember about the Phillies, when the likes of Mike Grace and Mike Mimbs and Mike Williams were actually what passed for the future of the rotation during those years. (Williams doesn't really belong on that list but couldn't resist adding another Mike.)
Certainly the Phillies have benefitted from it, if it is real, just with Falter last year and Sanchez this year. Neither were brand new, but new enough.