... would "seem" to be the case but if the take up is low (which shouldn't be for a "true" employer 100% paid DB plan), why bother. Allocate that "expense" to the employee's "total compensation" package would be more (or at least esthetically) "competitive".Sometimes it's to be competitive with other employers.
... no doubt SERP would be available only to very larger employers and usually those up at the top.Even few still make the SERP available to all employees.
There's also the companies with DB pensions that only the employer contributes to. I forget which big 6 bank opened one of these in 2009.
My point being, wouldn't the SERP be an additional cost/liability to the "employer"? Moreover, I don't think a SERP would require an employee contribution (which I think is convoluted for DB plans in the first place).