[mjn]

Yes, the standard is one paid sabbatical every 7 years. And in some fields it comes with the de-facto obligation to write a book during that year. It is also the case that at any given time many of Harvard's faculty (in particular) are on sabbatical, but most of those are unpaid sabbaticals. Ivy League profs often take time off to be visiting scholars at other institutions, or at the UN or IMF and such. But they don't normally get paid for that; they take an unpaid sabbatical and are paid by the institution they visit, or by a research grant.

But in any case how much Ivy Leagues cost is hardly the main question of public interest; they could cost $80k for all I care. It's the decreasing affordability of systems like the University of California that is the major problem from a public-education standpoint, and that is mainly due to decreased funding.