I do think the cool thing about what we're building is you don't really have to understand exactly what homomorphic encryption is to use / benefit from it.
We're really just building a database that can't learn what rows you read, which is useful (and practical!) across a bunch of domains. The fact that it uses homomorphic encryption under the hood is cool, but hopefully you don't need to get too bogged down in the details to use it.
I am not terribly confident that over the next 5 years we will see anything like a 10x or 100x improvement in general fully homomorphic encryption.
Instead, I think we already have some domains for which FHE is really practical today (like private information retrieval), and we should focus on those. In these domains, the cost overhead of PIR is less than ~10-100x, and negligible for many real-world scenarios.