Are you saying SQL survived only because people have used it for so long and therefore its sustained use isn't an indicator of value?
OP said that it's probably good because it has lasted so long. I would agree.
Or... It sucks as badly now as it did back then.
It's easy sit in an armchair and point out all the warts on specific tech, but if you were to build a better solution to broad technology segments like this, and magically get adoption, you'd find that you only understood 5% of the application space, and your better version is subject to whole swaths of criticism that you didn't anticipate. Better to find one small/simple thing you can do well and build from there.
Also isn't this a similar idea to what FileMaker Bento did?
There might be performance improvements and better abstractions from moving what is traditionally known as "application code" into a place where it has better, more direct, access to the data.
I'm not saying that we should be throwing out SQL and starting over, but if there are massive gains to be had by letting the database do MORE (or redefining what the database actually is, maybe "merging" it with the application code so that this new "thing" has knowledge of both how the data is stored as well as how it will be processed), why not explore those?
Honestly I'm being vague because I have no real idea what I'm talking about here, but if you look at the past, you see this in many other areas. First the FPU joined the CPU, then the GPU joined the CPU, then phones happened and you get the SOC where everything is in the "CPU".
I see where OP is coming from. The data resides in database but there is no "easy" may to make it available to end users. So everyone does their own thing anyway. Yes I appreciate a well curated database but something is amiss.
I don't want to have to know about how my database works internally just to implement a new feature in my application. I don't want to worry about a junior dev corrupting data while building a login page.
My "simple old-school" database is reliable and consistent BECAUSE it's been tested for years. My application server is not because it's solving a new problem (And that's OK, I won't lose customer data if someone can't login).