Will Apple's next iPad reach performance nirvana with a monster quad-core chip? Nirvana, maybe, but not necessarily via quad-core.
But let's put aside whether Apple's latest chip will be quad-core for a minute and look at what others are doing. (See a post at The Verge on this topic too.)
One of the leading lights among ARM processor suppliers is Texas Instruments. They've made it clear that they're not going quad-core this year and not even next year (necessarily) with their first next-gen OMAP5 chips.