While I agree that in the long run we might be able to do better than Enlighten and that in the short run there are a lot of optimizations that could be done for lightmass, my point was explicitly about being able to use enlighten in the here and now.
For us and probably others as well, long build times are not a big issue compared to the amount of time spent on unwrapping lightmap uvs and setting up lighting in addition to the general limitations of using dynamic lighting in interiors as described above. Hiring more artists is way more expensive than adding hardware - so build times are actually comparably cheap to deal with.