Because it wouldn't make it faster... bilinear reaches the same speed like AMaZE cached - at least on my very old Core2Duo, and newer systems should be even faster.
How did MlRawViewer achieved real time playback? But even there that were pretty huge loading times, I don't even know why do we have loading times honestly, is it because of mlv structure?
@togg
Does not matter how long clip is, decompressing is done per frame and on the fly. It is barely noticeable even in MLVFS.
Edit: You just have to try it yourself and all questions will go away 
Edit2: Nobody's willing to use uncompressed MLVs any more b/c of the data rate reduction and higher resolution recording possibility.
waaaait, this is not my experience at all. I have loading times at the beginning of each mlv.
regarding uncompressed/compressed I guess I'm catchin up late because of the forum/development organization. Right now is very very hard to find relevant info and recapitulative topics. I mean even the fragmentation of nightly/experimental isn't helping.