I have read what every one has said and I agree that there are bunch of ways to extend battery life... Shut services, locations, etc etc etc. That's not the point I am trying to make.
What I am saying is whether you keep all those apps and services off or on... If you have WiFi on or off will make a huge difference.
All these things are to extend battery life, not to fix broken battery life. Working with an earlier example of a sports car... I buy a sports car with 8 cylinder engine and big battery and what not. But then I realize oh damn...due to some fault I am not able to squeeze 500 horse power that I am supposed to get... But I am only getting 300 hp. Well I am screwed... Maybe if I don't use the exhaust system to its full potential, I can get some power, or maybe if I turn the engine down from v8 to v6...i can get to 400 hp maybe... Still not full potential but better. But that's not why I bought the car. I want the car that performs to its potential and then I can make whatever tweaks I want to one way or the other to make it even better.
I think what people are not grasping here is... That i am not saying that I can't improve my battery life by doing certain things. Yes my battery life sucks when on WiFi and I can turn off various services and make it suck a little less. But I would like it to not suck such dramatically on WiFi compared to 4G...and then I can make it even better if I choose to by turning certain services (location, power saving etc) off. Turnings these on and off should be my decision but all else equal... Turning WiFi on should not cut your battery life in half.
I know US carriers suck when it comes to bloatware... I am not arguing whether they should have all that on our not... Thats a separate discussion. All I am saying is all equal turning WiFi on its killing battery.
Not sure if I was able to explain myself but this was the best I could do.