To say WCW failed because they only cared about ratings, means your thought process is lethargic or inarticulate.
Ratings is viewers! which in turn creates revenue/money.
You cannot fault a company to go out of business cause they wanted ratings, that's why you start a televised product to carry key quality's such as ratings and revenue to your disposal for your product to thrive on.
Problem was the booking department.
It's quite fucking obvious they cared more about Nitro than their own PPV's. Why else would you constantly book Nitro in the Superdome & Georgia Dome, yet book PPV's in the Scope and a shithole like the Civic Center in Charleston, WV?
Ratings is viewers? Way to crack that case, Inspector Gadget.
You CAN fault a company for going out of business because they wanted ratings, simply because their goal was to put Vince out of business and it bit them in the ass. From day 1, WCW was losing money and not because of the booking (aside from nWo, 1989-1990 saw some of the best angles in WCW history).
Turner didn't give a damn about the money, he wanted to put Vince out of business and didn't care how it happened. Wonder why TNA doesn't take that approach? Because it's the equivalent of suicide.
In a way, it's a combination of booking & caring too much about ratings that saw them never attain a win after October 1998. For 1, some genius completely overloaded Halloween Havoc 1998, which saw Goldberg/DDP lose the PPV feed minutes into the match. For 2, the logic of spoiling Mankind's title win, in a way to attract more viewers to your product was the dumbest idea ever.
Last but not least, it wasn't a good idea to book matches like nWo Savage/nWo Hogan, Goldberg/Hogan or Bret/Hogan vs. Sting/Luger with absolutely no build up, just so you can pop a high number, when you could have built it up over weeks on Nitro and do it on PPV, which would have attracted high ratings, as well as a pretty decent buyrate.
They didn't plan long term, they planned in the NOW and planning in the NOW is the reason they're not here NOW.
Say what you want about Bischoff but WCW achieved it's biggest success with him running the company, which is a big accomplishment, considering his only experience in wrestling was as a commentator. But, he had, at the time, original ideas. And it says a lot that he did better than guys like Cornette, Crockett (to an extent), Dusty, Kevin Sullivan, Laurinitis and Terry Taylor, guys who had actual experience in the business but usually clogged the show up with bullshit that it became unbearable. And Vince Russo made it even worse.
Bottom line, WCW failed because it's only focus was on beating Vince and if you noticed their product during those days, it shouldn't be a secret. They held off on potentially big money matches just so they could attain a ratings win over Vince. It was good for the now but what happens when Vince steps his product up, which he did? They hit the panic button and didn't know what to do because they were driven by the thought of putting WWE out of business.