I'm convinced there's more noise but I'm not sure how much of it is really more signal. Consider growing a potato and searching for that term on Google. I'm betting a lot of articles are going to be somewhat junky SEO spam that's repeating the same few pieces of info. Whereas if you were to go to a garden center or library, and find a book or pamphlet on growing a potato, that's probably going to be great information and very comprehensive, and covers a lot more than those short articles ever do. This generation wasn't without good information. They were consulting things like the Haynes manual for their cars the same as your mechanic does today, or reading on the pros and cons of different truss designs from books available in the hardware store.
For other tasks, some things have simply become a lot more complicated to work on. Electronics were a lot simpler in older times, for instance; swapping out a surface mount quad flat package will require a lot more "finesse" than swapping out a 1960s capacitor. Cars too have gotten more electronics and software. Despite this, there are definitely still people that have the skills to repair modern electronics and cars. (I will say that these types are often hampered by manufacturers that seem hostile to the idea of users being able to practically repair devices, hence the "right to repair" movement being a thing these days.)