Pepsi vs. Coke Logo Evolution

I ran across this image on EatLiver.com today.

Very interesting in the fact that Coca Cola has not changed its logo since its birth in 1885, 13 years before Pepsi came about. While Coca Cola's logo remained the same to this day, Pepsi went through numerous logo changes and yet they are still equal competitors in the soft drink oligopoly. Judging by Pepsi's first logo (which was poorly executed in my opinion), recreating the logo could only have helped them. They could still even get away with using the 1973 logo today which, to me, is the most recognizable.
Speaking of pop that has gone to the wayside... whatever happened to Royal Crown Cola? Barrelhead Root Beer? Why did Faygo change Moonshine to Moon Mist?
The 2008 Pepsi logo is a direct Obama Change logo ripoff.