The secret to Pandora is to never give thumbs up but religiously thumbs down anything you don't like. Then it's constantly searching for new things you like related to the original theme!
But also, yes that was the original thought process.
100%. I bought into the "thumbs up what you like and get more of it" when I signed up for Pandora, and that quickly led to getting the same thumbs up songs over and over...
Fortunately with Pandora you could create a new station that wasn't aware of the thumbs so it was able to work around, but it took me a while to figure that out and stop thumbing up
But also, yes that was the original thought process.