Sure, some C code, some html, a table here, a colspan there, and you can have a website made by a single person... if we want a website to look like it was made on an 1980s computer by a single person.
If you're not that person, it's fine. Some people still just use notepad and write html like it's 1999. Other have both kernel experience, and have picked up react at some point in the past ten years. Plus LLMs write css these days, so no colspan needed.
At the rate LLMs are improving, that certainly seems like a possibility, but until they do, why would you need one for that? Kernel C makes sense. CSS is the problem here.
Or, you can have a decent website made by a single person. It's not that hard to learn basic HTML5, enough ARIA semantics to know not to use ARIA, a programming language with decent synchronisation primitives that supports CGI, an SQL dialect and the principles of relational database design, enough JavaScript to use MDN, enough CSS to use MDN, the basics of server maintenance, TLS certificate provision, and DNS.
If you want to do your own networking, or run email, that's a whole 'nother specialism; but just running a website is easy enough for one person to do.