I'm (mostly) a believer too, and I think AI makes using and improving these existing frameworks and libraries even easier.
You mentioned matplotlib, why does it make sense to pay for a bunch of AI agents to re-invent what matplotlib does and fix bugs that matplotlib has already fixed, instead of just having AI agents write code that uses it.
I mean, the thesis of the post is odd. I'll grant you that.
I work mostly with python (the vast majority is pure python), flask, and htmx, with a bit of vanilla js thrown in.
In a sense, I can understand the thesis. On the one hand Flask is a fantastic tool, with a reasonable abstraction given the high complexity. I wouldn't want to replace Flask. On the otherhand HTMX is a great tool, but often imperfect for what I'm exactly trying to do. Most people would say "well just just React!" except that I honestly loathe working with js, and unless someone is paying me, I'll do it in python. I could see working with an LLM to build a custom tool to make a version of HTMX that better interacts with Flask in the way I want it to.
In fact, in my project I'm working on now I'm building complex heatmap illustrations that require a ton of dataprocessing, so I've been building a model to reduce the NP hard aspects of that process. However, the illustrations are the point, and I've already had a back and forth with the LLM about porting the project into HTML, or some web based version of illustration at least, simply because I'd have much more control over the illustrations. Right now, matplotlib still suits me just fine, but if I had to port it, I could see just building my own tool instead of finding an existing framework and learning it.
Frameworks are mostly useful because of group knowledge. I learn Flask because I don't want to build all these tools from scratch, and because I makes me literate in a very common language. The author is suggesting that these barriers -- at least for your own code -- functionally don't exist anymore. Learning a new framework is about as labor intensive as learning one you're creating as you go. I think it's short-sighted, yes, but depending on the project, yea when it's trivial to build the tool you want, it's tempting to do that instead learning to use a similar tool that needs two adapters attached to it to work well on the job you're trying to do.
At the same time, this is about scope. Anyone throwing out React because they want to just "invent their own entire web framework" is just being an idiot.