This is obliquely addressed. The methodology of value investing is well known by now. The goal is to buy underpriced stocks.
If you want to play that game you have to compete against large firms that have buildings full of people looking into the fundamentals of the companies. Or you need some other informational advantage.
Otherwise you are almost certainly buying correctly-valued stocks. That's not value investing, but you can do something else that is useful, like buy an index.
I don't believe that the stock market is efficient in the way you are suggesting.
For one thing, there are lots of companies I can buy into that Warren Buffet can't, because he can't take a meaningful (to him) position, because he would end up owning the entire company. And even that may not be enough to be meaningful to him.
I suspect this phenomenon also exists for firms and institutions much smaller than Buffet. It may not be that they would own the whole company, but simply that they would own too much of it and/or move the price on their own.
For another thing, lots of investors are irrational. They follow fads. There are certainly opportunities for contrarians.
> you can do something else that is useful, like buy an index
That is precisely not useful in terms of efficient price discovery, though it may be "useful" to the individual investor who has better things to do with his or her time. That is one kind of behavior that causes inefficient markets that careful investors can then exploit.
If you want to play that game you have to compete against large firms that have buildings full of people looking into the fundamentals of the companies. Or you need some other informational advantage.
Otherwise you are almost certainly buying correctly-valued stocks. That's not value investing, but you can do something else that is useful, like buy an index.