I think you are mostly right, but you can make some headway by targeting long tail keywords with long tail ads leading to long tail landing pages. That can boost your CTR and move you up a little, and also boost your conversion rate making it worth it to even be there. If you try long tail keywords with the same ad and landing page you would use for broad matched core keywords, expect to go nowhere.
Martinitbuster is right about the weight classes, though. Also, if you aren't in the same ballpark price-wise, your CTR won't make up for it. So, sometimes you will only break even by not playing at all.