Well, I'd say it's a bit muddled. Pure STM systems have seen limited success, mostly on the jvm, particularly clojure. But as a technology it's not spread widely in the industry, despite the fundamental advantage of composability. I personally would attribute this to a sort of gulf created by two common approaches:

1. It's become very common to structure software as a stateless service cluster backed by a stateful database technology. Most of the databases used in this approach would not be described as STM, but the net effect to the application is similar, even if involving more layers and complexity.

2. People have gotten pretty comfortable with simple mutex patterns connected by queues of various sorts. This is a sort of worse is better situation, where the simplicity and high performance of a mutex protected whatever in a toy test or microbenchmark is far more efficient than STM. However, a system composed of many of these mutex protected islands proves a whole different beast indeed. STM has largely been criticized from the perspective of the former, vs the latter.

There are many people who have made the observation that transactional concurrency control, state of the art garbage collection, and even file systems have been converging on similar features. This is being driven by the common constrains on both sides of what hardware and humans expect. In particular with persistent memory, I think you'll see all three of these unify into a single design, because systems that attempt to solve these problems separately will have very inferior match to the hardware.