Read on Twitter
Peer reviews are, slowly, becoming more portable. A limited number of publishers are allowing authors to take reviews (typically received with a rejection letter) from one journal to another. I think this will accelerate, with minor short-term but big long-term benefits. 
More portability will happen partly because the traditional system of prohibiting it was nonsensical; it meant there was a lot of redundancy (waste of reviewer and author time) in the traditional system. But that certainly isn't a *sufficient* reason to expect change, because
the system maintained the inefficient equilibrium of near-universal prohibition for many decades. But such an equilibrium is unstable once a certain number of actors break the prohibition, and thus people at other journals and publishers have to admit it is acceptable behavior,
at least in some circumstances, and have to answer "Why not for our circumstances?"
And for an individual journal publisher, e.g. Elsevier, encouraging forwarding of reviews to other Elsevier journals increases throughput, which can increase revenue.
And for an individual journal publisher, e.g. Elsevier, encouraging forwarding of reviews to other Elsevier journals increases throughput, which can increase revenue.
But Elsevier and Wiley never did it, maybe because nobody wants to mess with a system that brings in >25% operating profits. But now that there is a bit of pressure on subscription revenue growth, they have to be looking to increase efficiency.
Still this might not be sufficient to get them to change policy because they know that once they do so and researchers and editors become used to using reviews from other journals, which could have a negative effect on resources (reviews) traditionally exclusive to Elsevier.
Authors and academic editors might (eventually) not accept a policy of taking reviews only from other Elsevier journals, and corporate may be unhappy with the idea of helping their competitors by providing then with reviews, so they don't want to start down this slippery slope.
However, other publishers such as PLoS , BMC, and others ( http://nprc.incf.org/ ) have already initiated a slide down the slippery slope. Norms of what's acceptable or natural to authors and editors gradually change, and eventually we end up with less redundancy.
Minor efficiency gains are nice, but what I'm most excited about is that a norm of sending reviews to other publishers also shifts a bit the normativeness of open peer review, which enables assessing how much vetting they received independently of publisher branding/reputation.
This hurts publishers who defend high profits by relying on the prestige they gradually accumulated in the non-transparent black-box journal management system closed review system, and thus reduces academia's dependence on them.
One of the journals that is happy to consider decision letters and reviews when submitted by the authors from other journals is Collabra:Psychology (where i am an associate editor).
I believe @Meta_Psy does too, is that right @RickCarlsson? The reviews might then have to be made public, if they weren't already.
