"Solves" in what sense? Dependency resolution is an NP-hard problem; if the tool you're using is guaranteed to run quickly, then either (1) there are cases it can't handle but conda can, or (2) the tool's author has just proven P=NP.

The OP probably means "solved" as in "faster."

The original Conda solver is just badly optimized, whether through the implementation or a poor language choice. For years, user performance concerns were written off as just the price you pay for the correctness of an SAT.

Mamba was a third party rewrite that was a couple orders of magnitude faster. Users started leaving Conda for Mamba. It scared the Conda developer enough that they dropped whatever invisible back-end features they were prioritizing, and within months they added a feature to install different dependency resolution libraries, targeting Mamba first.

It is NP-hard, but realistically that should not be a concern for most dependency management questions users throw at it? Just how many variables are folks imagining are in a typical dependency tree?

Google claims the average number of dependencies is 35. My gut is most of these do not have too many versions, all told. Is this really big enough that you'd expect it to be the bottleneck?

It probably has a heuristic for it