Yes, this is a good point and is definitely one of the values that content-based recommendation can bring. Unfortunately at the moment we don’t have the resources or research tools available to produce such a system that we’re happy with distributing.
We know that the MusicBrainz community has a strong history of contributing metadata about music, including for less common stuff. We hope that we can rely on this community to help us build a good initial set of data. Perhaps in the future we can take this data and see what else we can do with it.
Part of the limitation of the current version of AcousticBrainz is that much of the data is also of low quality. For example, we have only a few models that work with “genre”, and they all have a very small number of categories. In comparison, we were able to tag over a million new recordings with hundreds of genre tags by collecting user-contributed data, so there is definitely value in this approach.