Funnily enough, I think one the original IBM PC killer apps was exactly that - dBase III https://en.wikipedia.org/wiki/DBase

MS Access was the usurper of dBase's crown. And then Excel took over ...

I would mention also (although it didn't have much success in the end) the Borland database, Paradox for Windows:

https://en.wikipedia.org/wiki/Paradox_(database)

I am not at all a programmer, but I remember that at least in early version(s) MS Access (circa 1994, Windows 3.1 times) was well behind Paradox in usability.

Access is literally this, and it never caught on.

The are a ton of benefits to enforcing data integrity like data types, foreign keys, etc., but it also adds a ton of friction. Users encounter tons of frustrating errors while simply copying and pasting things, because certain values aren't allowed in certain columns.

I think you'd need human-readable datatypes displayed beneath each column name, adjustable by just clicking it and changing it in the drop-down, and massive flexibility out of the box. You shouldn't throw hard errors - just visually mark the invalid values red or pink or whatever, and let the user fix then before writing them to the database.

There is actually a tool that does exactly what you describe. It's called baserow :) https://baserow.io/

It's open source and hosted in the cloud. It has an excel like interface that you can share and work on with others.

There is actually a tool like that, it's called Baserow :)

It does exactly what you mentioned. It's a cloud hosted, database tool with an excel like interface and collaboration features.

It is also open source and can be self hosted, but you can use the oficial website to use it directly without having to use it yourself :)

Forgive my ignorance, but isn't that what Airtable is?

A modern web-based cloud-hosted access implementation would be a killer app for web-2.0.