I only ever played with DCOM and Transaction Server, and never in production, but I do wonder what about that tech stack made it so absolutely unworkable, and such a technological dead-end? Did anyone ever manage to make it work?
What I remember is that there were social reasons, market reasons, and technical reasons that MTS didn't pan out. First, Microsoft was out-of-fashion in startup culture. Second, the exploding internet boom had little demand for distributed transactions. Third, COM was a proprietary technology that relied on C++ at a time when developers were flocking to easier memory-managed languages like Java, which was or at least was perceived to be more "open." I'm sure there were other reasons, but that's what looms in my mind.