As far as I know, litigators do spend a fair amount of time researching cases as it there job to assemble a case that is capable of being presented in court - although most litigation gets settled before going anywhere near a court.
However, in most law firms I know litigators are in the minority - and I don't think the likes of corporate lawyers spend much time researching cases?
Why should the final price tag remain the same? Free market economics says that if we introduce efficiencies, the price comes down, and/or fewer people produce the same output. In general (exception is music, as far as I can tell) that's the case. Other labor markets have suffered horrible, drastic shake-outs, why not Law?