My information on this is secondhand/word-of-mouth but it is my understanding that at least some engineers at Yahoo have in fact been very handsomely compensated.

A friend of mine involved in offer negotiation at another company who was at one point (this was perhaps 5-6 years ago) trying to poach some high level Yahoo infrastructure folks told me that a lot of senior Yahoo engineers had straight cash compensation packages that rivaled what Google or Facebook would pay in cash + RSUs.

Presumably these were folks involved in directly maintaining core revenue generating ad systems who would be very expensive and painful to lose / replace.