While I don't think LLMs can make great production ready code for the web yet, I think it's on the way.
Right now, AI that can write code is trained on code that isn't very semantic or accessible because on the whole code for the web that's written by humans isn't very semantic or accessible. The AI will then produce code that isn't very semantic or accessible and that will continue to propagate as AIs see that pattern repeated over and over again.
It's not always going to be this way, though. As LLMs understand and incorporate documentation and specifications alongside actual code they will be able to make code that is pretty close to perfect.
I don't think it'll be a particularly long time until designers can produce the UI they want visually and export to high quality code. I also think that a wave of start ups will care less about the semantics and accessibility than speed to market and not giving people a salary equity.
To cut a long story short; I think it's time to stop putting off diversifying my knowledge and to start to learn at least one other language. It's going to take discipline because honestly, I don't especially enjoy writing code. I like the outcomes, not the process.