This is why I don't call for a boycott on submitting to closed-access publications. It's a nice gesture if you can afford it, but the impact of any given person seems disproportionately low given the potentially high potential professional cost as long as those venues are regarded as among the "top" publications in a field. But there's something more effective (and less costly) that we can do instead.
I call on our community to refuse to volunteer as reviewers, PC members, editors, or editorial board members of closed-access publications, and to perform proportionately more service for those that support open-access. If enough respected members of a field do this, the prestige and power of the close-access holdouts will diminish (or they'll shift to open access). And even junior people can generally afford to be selective about who they review for.
And, of course, we should support professional organizations that have open-access policies (such as Usenix).