I disagree slightly with the idea that United regularly spent huge sums before the Glazers, especially not during the PLC years.
Yes they certainly broke the transfer record a few times (Pallister, Keane, Cole, Veron and Ferdinand if I'm right), but given they were the biggest club in England from 1991 (when the club went public) to 2005 (when the Glazers bought it), it's not surprising they broke the record. It's not as if they were breaking it every year, as you might expect the biggest and richest club in the country to do. Plus Ferguson's net spend was very low; aside from that handful of big-money signings he didn't buy that many players, and most of the first title-winning team were incredible bargains (Cantona, Schmeichel, Irwin, Bruce, Kanchelskis, Sharpe) rather than big-money buys.
That said, what the original poster said was spot on. There was no great commitment to youth, apart from that one summer in '95. Ferguson bought all the key players bar Giggs in his first successful team (the 92-94 one) and the 98-99 season was preceded by what, for United, was a big-spending summer (Yorke, Cole and Blomqvist coming in).
Aside from the amazing Beckham/Scholes/Nevilles/Butt/Giggs crop, we hardly promoted any youngsters. Who else came through to establish themselves under Fergie? O'Shea, Brown, Evans and Fletcher are the only ones that spring to mind. When you think of it like that, United's commitment to youth under Ferguson wasn't that great at all.