Of course, that's the point. It takes such talent in academics to command the sort of job liquidity at the high end that is taken for granted in industry.
That Terence Tao is being paid twice the average tenured salary at Harvard while he's at UCLA speaks to both our points. Unlike most professors, Terence Tao is paid by UCLA what he could hypothetically get if he went to Harvard (speculatively, of course). Other professors would face much more friction in packing up their bags and hopping into tenured positions at peer institutions or higher.
That Terence Tao is being paid twice the average tenured salary at Harvard while he's at UCLA speaks to both our points. Unlike most professors, Terence Tao is paid by UCLA what he could hypothetically get if he went to Harvard (speculatively, of course). Other professors would face much more friction in packing up their bags and hopping into tenured positions at peer institutions or higher.