To give you an idea, here are all I've found. I'm sure there are other ones out there. I've also seen many on IndieHackers, but these are all the ones that have raised VC capital:
Rows.com
Clay.com
Spreadsheet.com
GetGrist.com
Nobodb.com
Retool.com
Equals.app
Coefficient.io
ActionDesk.io
Parabola.io
Rowy.io
They all seem to have been formed in the past 3 years, have raised funding in the $10 million range and all seem to do the same exact same things in slightly different ways. Basically import in data from various Databases and other sources like Twitter and Instagram and do excel operations on the data as well as some other additional functionalities they've added and generate charts. I'm not even sure if this is solving a real problem. Does anyone here have experience with this space or know more details about it or have used any of these SaaS products?
The existence of so many apps with such basic computer functions does not surprise me because you can implement it (at the detail level) in so many different ways (let the market decide the winner)
The sudden proliferation is another matter. I think it is just part of the recent (and more general) wave to build "higher level" (=no-code) platforms. Here, its is more "Data processing" oriented ones, that is all.
I regularly work with intelligent people (who aren't techies) who by themselves figure out their project needs to be relational all by themselves (knowing nothing about SQL).
I think, and I guess these companies do, that there must be a market for those millions of people who want to manage a few thousand rows of project data but are never going to learn SQL + web development to put a UI on it, but are struggling to keep their data managed "logically" and easily.