Thanks for the example, I'm aware of Notmuch but had no idea it relied on Xapian. However, back to my original point, there's simply not enough people or large

Thanks for the example, I'm aware of Notmuch but had no idea it relied on Xapian. However, back to my original point, there's simply not enough people or large projects/companies that rely on and use Xapian. I'm 99% positive that there is less than a handful of people at any of the last two Fortune 500 companies I've worked for that even knows what Notmuch is. But everyone knows Elastic, MongoDB, etc.. Again, I don't think Xapian is a bad tool or that it's underperforming by any stretch, but OP should not be surprised at all that most people have not heard of it.