Yes but some people DO still vote for those smaller parties [...]
I still don't think it's fair to draw the conclusion that those who vote for the primary parties must be at least mildly satisfied with their representation. Even if the tables turn eventually, in the meantime, a lot of people (myself included) have voted for a primary party knowing full well that, at best, to vote for the party I really wanted was a wasted vote.
Or, at the worst, if a ton of us who normally vote Republican, for example, decide to back a Libertarian candidate, at least the first time around it's more likely that the party we voted for will fail and that the one that we
really don't want to see in charge will have an advantage over the Republican party for it. Often, a vote is less a vote for that party and more of one against the one you really want to stick it to.