Clients are wise enough these days that they just care about the bottom line. They want to know: how much will this case that’s in discovery cost me this quarter (and can you help me justify it to my boss)? Often you give a realistic number and the client pushes back, which is how you end up with 10-20% of time being written off. This is true at every level of firm.
Within this framework, lawyers have an incentive to be efficient. If you cut your hours so you write off 10% instead of 20%, you’ve freed up hours you could spend on new billable work. If you enter into a flat fee arrangement (which in various permutations are very common), the only way you come out ahead if by harnessing efficiencies. I think most law firm managers are numerate enough to realize these things by now.
The challenges to adoption are risk. Law firms can’t push back the release date because the software isn’t ready. That makes them very conservative about changing their processes. Cost-benefit is also an issue. Even the largest law firms are relatively small companies. All major business decisions are made by lawyers, and not even the managing partner works more than part time on administration. They don’t have the bandwidth to implement software X that majorly improves some specific process Y. For the effort to be worth it technology has to deliver cross-cutting improvements.