[eru]

In contrast, software transactional memory is still a pretty neat abstraction for some concurrency problems.

(And, of course, hardware transactional memory can be used to implement 'software' transactional memory faster than in software.)

However, STM only really works well in languages that are pure by default, like eg Haskell (or perhaps Erlang might be close enough). In a language with pervasive mutations and side effects, it's too annoying to use. Microsoft tried to make it work for .net for a while, and gave up.