I'll have to give your book a read because it reflects some vague ideas I've been having. It feels like having "more liquidity" in the job market could benefit both employees and employers: it would make it easier for me to find a job that's a good fit and to adjust my role as my circumstances change; similarly, it lets companies be more flexible.
My theory is that this is the sort of thing that's only a problem relative to our expectations. If everybody expected people to move between jobs more often, it would have a significantly lower cost while conferring the benefits I mentioned above.
Then again, I'm the sort of person who can't imagine spending 40 years climbing a hierarchy at a big corporation, so I might just be fundamentally different from the people who actively want that...