In one way an interesting topic, since there seems to be so many views and opinions about the pros and cons with integrated amps...
On the other hand, it is an irrelevant topic, because the real issue here must be if an integrated amp regarding sound quality can match (or even exceed) a separated pre- and poweramp if they have the same price tag...? My answer is YES, they sure can!
If you look at some of the best and most ambitious integrated amps out there, for example the Gryphon Diablo 300, Mark Levinson No 585, Mcintosh MA9000, Musical Fidelity Nuvista 600/800 and even the Marantz PM-10, all of them getting raving reviews in Audiophile magazines, can of course match and be even better than separated combos in the same price range. The sound quality from an amplifier doesn´t improve just by separating all the units in two or three different boxes, It´s more about the individual components inside and how well those components work together to create the best possible sound. Isolation between different components is important, but short circuitry is important too.
Most separated amps are in a totally different price range and it would not be fair to compare a $10-15k integrated amp with a pre- and poweramp for more than $40-50k... On the other hand, putting everything in one box makes the production cheaper in the first place! Like someone recently mentioned, most people look for most "Bang for the buck", and integrated amps gives them just that and sometimes even moore... I´ve had several integrated amps over a nearly 30-35 year span and all I can say is that I probably had to spend twice the money each time to actually hear any noticeable difference. If I would have chosen separeted units it would have been even moore expensive.
If you have more money than you can spend, of course go for a separated amp, believe it would produce better sound than any existing integrated amp, and be happy! But IMHO you are only fooling yourself!