In the old Mac days, the product to beat was FileMaker Pro. Apparently it's still developed, but I've never seen it used in a Windows environment. MS Access is awful. Everyone "normal" just uses Excel for things that really need a relational database!
In the current world of autosave-everything, that wouldn't be a problem, but against a backdrop of "Nothing is permanent until you hit ctrl+s", it was a complete headfuck to suddenly be unable to back out your changes because you accidentally typed something into the wrong cell.
There were lots of other issues with Access too, but I think that aspect was key to it being daunting and off-putting.
If someone sent you an excel file, you'd feel comfortable trying things and playing around with it. If you really needed, you could copy a sheet and easily make changes without fear.
If someone sent you an access file, you'd be scared of making changes you couldn't back out of. When you don't enable experimentation, it's hard for users to get to grips with unfamiliar software.
So I really think that a spreadsheet was (and still is) way more intuitive at first, and if you were "bold enough" to investigate macros you would just try to solve all your problems with something you had already a good mental image of.
Another product to look to for inspiration is Lotus Notes whose object database with synchronization was way ahead of its time (with all patents expired!)
There's your answer. Excel is good enough for most people's needs, though I will admit that its failure mode is that people tend to get really good at it when they start pushing its boundaries to the point where a DB would serve them better.