Renegade,
I know that this all this philosophy of science stuff sounds fatuous, or silly, or pointless. When I was first exposed to it all, it took me many hours over many months to really get my head around it. It is, certainly, counter-intuitive, and I had lots of trouble with it.
But, trust me, this is how scientific progress works - research programs 'compete' in the manner described above. Old theories cannot be disproven without a newer and better theory to take their place. The entire history of the scientific progress of the human race is essentially based on this.
People who are much smarter than I (and probably most people here) have spent decades discussing the issue of "how do we know progress when we see it?" Everything I've sid above, in my own poorly worded way, comes straight out of the mouths of people like David Hume, Karl Popper, Imre Lakatos, and so forth.
I sympathize greatly with your frustration. (I don't mean for that to sound arrogant - it probably does - sorry). I spent many hours in classes arguing the exact same thing as you have been to my professors. Eventually, I came to understand what they were saying, and why they were right. I can only say that it was extremely enlightening for me, and quite formative.
With that in mind, I can only urge you to not give up on this line of reasoning - I'm not trying to make anyone feel bad or stupid (although, again, I recognize that my manner of speech does sometimes come across like that - again, very sorry for that) - I am just trying to impart that same enlightenment that I felt when I really, finally, after years, understood what scientific progress and the growth of human knowledge was all about.
Useful citations for above referenced philosophers:
http://en.wikipedia.org/wiki/David_Hume (see especially the problem of induction)
http://plato.stanford.edu/entries/popper/
http://en.wikipedia.org/wiki/Karl_Popper (see especially section on philosophy of science)
http://en.wikipedia.org/wiki/Imre_Lakatos (see especially section on research programs)
For a counter-vailing view of all this, Thomas Kuhn is interesting (although largely debunked and I don't think anyone puts much stock in him anymore - I could be wrong on that). The Wiki article on him is sparse, but it has good links elsewhere I suspect -
http://en.wikipedia.org/wiki/Thomas_Kuhn)
And let me say "thanks" for allowing me to debate this topic, especially given that I often come across like an arrogant SOB with a bad attidude.
Philosophy of science is a subject I find fascinating and close to my heart, and getting practice in discussing it with critics it is invaluable.
Thanks,
AMF