Is a listing agent really worth 6%

I am a discount Realtor here in Dallas and was wondering thoughts on why exactly a listing agent deserves as much as a buying agent.  What tangible things to listing agents do that deserve this extra percentage?  Print advertisement to me is not a tangible or effective medium.  My basic opinion as a newbie is that if the house is listed on the MLS with nice pictures and description and is priced right for the area it will sell.  

99% of the time it will be shown by another agent and as long as they get their 3% they should be happy.  As for listing honestly it take maybe six maybe 12 hours total to research, meet, take pictures, list online and also on google yahoo and other sites,  possibly send some blast emails out and then answering phone calls, which not many folks call directly from signs. 

Main question here is what other than the MLS actually sells properties and warrant a Listing agent getting the same pay as a buyers agent who spent time, maybe months showing countless houses.  

The reason I bring this up is that on a recent shortsale the bank approbed 5% commission and I only got 2.5% for being the Selling agent .  The listing agent in my opinion should have taken 2% and given me the whole 3%. 

Thanks

RJ