I think it was always the plan, in the meantime it served as a stick to beat Motorola/IBM with.
That really doesn't make a lot of sense, considering how many years they spent on PowerPC and how much they loved to place themselves in opposition to Intel. I seriously doubt that twelve years of PowerPC was just a phase they were going through while they plotted how best to dump the technology they'd invested all that time and money in.
Steve Jobs planned and wanted for Apple to switch to Intel x86 as early as late 90s. He was personally very dissatisfied with Motorola and their PPC chips and since Motorola also lost a lot of money when Jobs killed the clone market, there was no love between the two.
Got a reference for that? Granted Jobs was a capricious whacko when it came to picking directions for the company, I wouldn't be
surprised if he just up and decided that he wanted to change architectures, but the period from the late '90s to the laying to rest of PPC Macs in 2006 spanned a whole
three new generations of PowerPC Macs (G3, G4, and G5,) all of which were touted as the best thing since sliced bread and
way cooler than pokey old x86. These claims that Apple was secretly planning to get all buddy-buddy with Intel even while they were roundly abusing them in the press really just don't seem to fit.