From what I understand Ferguson did have these resources, but chose not to use them. He spent £60m his final season, 25m of that on RVP, who was no spring chicken, then £10m+ on Zaha - an expensive shot on a largely untested youth. The year before he spent £50m on Jones, Young and De Gea. Ferguson was never really one for going all out on a big name signing - though he could do if he wanted to, such as £31m on Berbatov, but the outlay he did spend suggests he had enough money to buy what he wanted.
Ferguson himself was always very vocal that he had the resource to use if he saw fit. However Ferguson had too much confidence in the like of Cleveley, Evans, Fletcher, Smalling etc to become good enough for Utd - Moyes and Van Gaal are spending to rectify those sort of presumptions (shame they haven't corrected those exact presumptions yet.....)
Whilst I wont be happy if this is our last deal - we need the back strengthening for sure. However I love this signing, gives us that extra something behind he strikers - weve been too lifeless an flat their for a few years, and no-one, bar Mata, gives me the confidence we can unlock a subborn, deep defence (which is most teams default setting against us)