[mrow84]

Probably because it would be expensive and risky to roll out something across a large, already existing network, but at the same time running an innovative "side project" may well be met by anxiety (and corresponding resistance) by those who aren't able to participate. It seems to me that both of these responses are fairly economically rational, given the corresponding risks.

Regulation could be useful here, if properly designed, by helping to alleviate the fears of those in the existing industry who are most likely to be directly affected by these useful innovations. Unfortunately, the allergic political response of some sectors of society to anything interventionist makes coming to reasonable arrangements quite difficult, so we just end up with something that isn't really that great for anyone.