True. And yet the world of investing (I'm not talking about market makers etc) is filled with funds whose composition is determined by everything except simply buying predictable cash flows for cheap, wherever you can find them.
I completely disagree.
You have to judge the (long term) investment in full context of the market, i.e. what other people are thinking about it, regulatory climate, geopolitical issues, taxation, position in the value chain, status of customers/suppliers etc..
And for some strategies - none of it is relevant. If you can make trades 0.1 seconds faster than anyone else, the nature of the approach will be such that you don't care anything about the company other than where it's price is now - and where it will probably be 0.1 seconds from now.