Just thinking out loud here...
Why isn't it more common to have, say, year-long faculty exchanges between relatively nearby colleges? “I'll trade you a senior anthropologist for a business prof and a second-round draft pick.” The faculty exchanged would be paid by their original institutions, and the time would count towards seniority at their original institutions. It would be restricted to folks with tenure, so there'd be no issue of how to count it on the tenure clock.
The costs would be minimal, especially if the program were voluntary (which it would have to be).
Some possible benefits:
Breaking up the inbreeding in some areas, even if only temporarily.
Exposing senior teaching faculty to the ways things are done at other colleges, to discourage provincialism and help spread good ideas more quickly.
Temporary staffing imbalances caused by, say, sabbaticals or maternity leaves could be covered by swapping folks from well-covered departments to get folks in shorthanded ones.
Relationships between neighboring colleges would be strengthened.
Some folks might notice that issues they've attributed to personalities are, in fact, structural.
Seems like a reasonable deal to me.
The swapping schools would have to be 'peers.' I don't see us sending our folks to Snooty U for a year, and I certainly don't think the faculty from Snooty U would last ten minutes here. (“Wait a minute. I teach how many sections? And where's my t.a.?”) But if we were to send a person or two each year to one of several other community colleges nearby, there wouldn't be an issue of mission shock.
Some time in another setting might allow a window into other possible ways of doing things. Some wouldn't make sense to bring back, but some might. And it might be healthy for some departments to hear from a secure visitor things like “jeez, you really don't have to do it that way. We do it this way.”
If something like this were available at your college, would you do it?