No, I don't think that's why it is addictive. That's why most of the population has access to it. That's perhaps why more expensive alternatives may not be as appealing to such large numbers.
There's a difference between market-based behavior based on cost and actual physiological brain behavior that is deliberately manipulated by the food manufacturer to make the brain want to eat more.
Those aren't the same thing at all - so when we know they're doing that and paying a lot of money in labs to achieve those flavors, I don't think it's correct at all to say "well as long as this food is cheap, it will be addictive."
Well whatever Blue Bell did to their ice cream to make it so damn good is fine by me. I'm more than ok with that addiction.
Now if Mickey D's puts something in that junk they call chicken nuggets, that is a different story. Someone should be jailed for such an offense.