My context at the time was that they were focused on doing single rounds of incremental updates, as in a PL UX, whereas DD aims at high throughput changes across multiple concurrent timestamps. That's old information though, so it could be very different now!
A while ago (2018), the people behind VIATRA performed a cross-technology benchmark where they compared their performance to 9 other incremental and non-incremental solutions (Neo4j, Drools, OCL, SQLite, MySQL, among others) [1]. Perhaps it could be interesting to rerun that benchmark while including Materialize?
This would give us a direct comparison between Materialize and other existing solutions. Their benchmark is however based on a kind of UX case, so the tests might be a bit biased towards that use case.
[1] The Train Benchmark: cross-technology performance evaluation of continuous model queries