>I'm sure I'm not alone in feeling the "deep expertise" OP laments was actually deeply inconvenient to many people.

And I'm sure I'm not alone in feeling that the convenience from ignoring the "deep expertise" and piling on hacks and lazy abstractions, all the way to modern multi-MB frameworks and Electron, is a regression.

Of course no one gives a shit about things like the user's computer/memory utilization. Or degraded experience. Or wasted bandwidth. Or the extra energy costs per 8 billion people - and the environmental impact.

>More people building things is straightforwardly good,

Is more people building public infrastructure "straightforwardly good"? If it means worse roads, worse bridges, systems that fail?

The same holds for software. And most things really.