I think you’re overestimating the value of building such support into a language, rather than using libraries/frameworks, and underestimating the difficulty of

I think you’re overestimating the value of building such support into a language, rather than using libraries/frameworks, and underestimating the difficulty of creating bespoke languages. Speaking as someone who’s actually tried what you’re suggesting—in a production project—and learned not to do it again, this whole conversation smacks of theory-crafting rather than practical experience. But I invite you to try it!