I think, Skyler, that the route to improvement here lies mostly in the sharpening of arguments and the anticipation of objections.

Large law firms have been over the last century pyramids that sell hours. Every lawyer's license carries with it a responsibility to serve the public, without fee or reward, some portion of the time. Firms that buy up lawyers' licenses wholesale and sell the lawyers' resulting hours retail want to put every hour that can be used out at its highest value. Partners want their obligations to work for free covered by other peoples' hours. They want their valuable associates to use all their hours valuably. But they want their statistics to look better than good enough, and they want people to feel that the hours contributed to fee-less feels-good practice are recognized, but not recognized—most of the time—enough for such an hour ever to seem more valuable than hours producing monetary value for the partners. (Labor market value, as you notice, in attracting and—sometimes—retaining non-partner talent is also part of the calculus). Achieving something like the right level of hours at something like the right level of cost is a firm-within-a-firm management problem.

If the lawyers doing the work were managed within the pro-bono organization, that would be sufficient: the pro-bono firm within the firm would have a budget, and would practice within the budget, much as an external non-profit practice like mine works. But then it wouldn't be providing emotional wonderfulness for everybody else. So the management of the lawyers remains within the structure of the hour-selling pyramid scheme, which destroys the effectiveness of the pro-bono practice it is trying to foster. Rarely is the low-level of bang for buck visible, however. Unless one has the perspective you speak from.

These large firm pro-bono operations could also lend out lawyers to external pro-bono organizations, of course. But that would mean paying high salaries to workers sitting alongside people earning much less for the same work under the management that is compelled to underpay them. And even I would be against allowing the firms to monetize their pro bono responsibilities by giving their ill-gotten cash to practices like mine.

So you could approach the question from an economic, moral or professional perspective and find new things to say that are more helpful to your case than an anecdote from S&C or rhetorical thwackings of associates' indifference to the "public radio pledge drive" quality of some law firm pro bono promotions.

But you should also anticipate some more of the most obvious objections. Your "what should we do instead?" answers are full of blue skies and songbirds, but they don't exactly add up to a platform. Not performing math to prove how virtuous they are will never appeal to these guys and you know it. If you don't allow them to keep public count of their mitzvahs, it's always going to be no deal. And if it's all such a botch then why shouldn't we just abolish pro bono requirements, and let the stupid virtuous lawyers who want to give away their time do it after we've sold every last hour we can wring from them, while we promote to partnership the ones who never outgrew Ayn Rand?