You make my point.
What better environment to learn and twiddle, than a reactive, constantly reevaluating interactive notebook?
All I am saying is that the d3 team needs a "getting started" page aimed at allowing a dev to include one script tag (or a single npm install) and then copy and paste examples from the example gallery to get it quickly working on their own test website.
I recently tried getting back into d3 and I gave up (opted for another low threshold SVG toolkit). It's fine if d3 is aimed at other people who want to use observable.... It's just not targeted at me anymore.
I'd recommend Plot instead: https://observablehq.com/@observablehq/plot
It also works as a pure JS library, just like D3, but is based on a grammar of graphics idea, like ggplot. It's not infinitely flexible, but flexible enough, and build to get quickly to a chart, with as few lines as possible.
Taking a dom node and hooking it into the dom is not magic in D3. All that obervable does is hook in any dom node you return for you.
I see you are passionate about defending Observable, and that's cool - it's a great piece of tech, but please remember that everybody's requirements are different and valid too.
It's like complaining that you can't learn how to drive in the evening, because there is a different sky color, than during the time you'll take your morning commute. The sky color is not the relevant nor difficult part.
I have my own (different) complaints about observable, but I'm sick and tired of bottom of the barrel programmers complaining about free stuff not being pre-digested enough for them.
Being softlocked into Observable is not a pro.
That's like trying to force every vim user into Jetbrain IDEs (both are great, not trying to start a flamewar here).
Sure an IDE will have more features (like Observable vs simple HTML file), but it's important to understand different people have different ways of doing things.
Like I said, everyone I've seen complain so far, always turn out to not even want to learn basic stuff.