Most people in America don't bother voting at all. Why? Well, some might say it is because simple ignorance, lack of time but most recognize that politics is filled with corruption and with a bunch of power seeking politicians that don't have any real interest in the good of the common man. So, within a system of obvious corruption within two parties it makes it pointless to vote either Dem or Repub because neither party will ever be successfully "changed" or taken over.
To not vote at all is the biggest waste, to vote within an obviously corrupt party for a corrupt politician within that party that has no intentions of ever being a reflection of you is also a wasted vote.
So, while voting 3rd party may technically be a wasted vote, it is still the best option. Unless of course you're under the delusion that voting for a corrupt politician is going to have some sort of positive impact.
And yes, the 2 party system has been around for a long time but I disagree with you about it never changing. Our country is capable of change as long as everyone comes together to make that change possible.