it’s even worse when they use it as a database...
Microsoft leaves Access out of many of its Office license plans, so it's an extra cost add-on to most people, hence uninteresting.
Filemaker is very nice, but even more costly in most cases.
I've never used Base in LibreOffice, but I also don't see people sharing their Base files, from which I infer that it isn't very popular. (Could be my myopia, though.)
Even if LibreOffice Base is gaining users much more rapidly than I think it is, they're missing the cloud component for offline and mobile users, which acts as a brake on adoption, given Office365 and Google Sheets pushing people to stick with spreadsheets when they want to share tabular data across sites and to mobile users.
Collabora Online is moving LibreOffice into the cloud, but they haven't done anything with Base, as far as I can see.
Apple's iWork web apps are very nice, and they have native clients on many of the platforms I care about, but there's no GUI database component at all.
Without a free, cloud-capable, normal-person focused GUI/web database system, I don't see Excel-as-database going away.
More seriously, It would be nice if MS added a better way to manage data tables outside of sheets in Excel. They have the underlying technologies to do it. It just needs a low friction UI.
Similarly, I used to struggle SO much with learning PHP frameworks because I had a "presentation first, data second, function third" methodology of doing things. After realizing how people were using Excel compared to my Access approach, sure I began to respect them more but that helped advance my own learning of frameworks.
But the absolute worst is when people turn excel based apps into a grid on a webpage.