Reducing "Other TSDBs" to log-structured-merge trees is misleading. Any large-scale TSDB has something sophisticated underneath and LSM is often just one tiny part of that. I would argue (as most do) that any TSDB "simply used an LSM" it would be doomed at any scale over time.
There was no reduction, it was intended as a pointer to one data structure some TSDBs are using underneath. I would bold and highlight the "etc" present there for you if the markup allowed it.
I hope a reader would become interested in what an LSM tree is (and perhaps as importantly isn't)
