I don't think they ever give up. They're just a vicious pest.

Try to offer another source of food for them or else, find their nest and get rid of it.

For me, they left when I switched to feeders (First Nature, I think) that had no yellow flowers or Bee guards. I started out this year with the standard Perky Pet feeders. As soon as the bees and wasps started gathering (I'm allergic), I did some research. Yellow attracts them. For several months, since switching all the feeders, no wasps or bees gathering here. One of the best things about these feeders is the base is interchangeable with the 16oz and 32 ounce reservoirs. We have found the 32 oz is better in high traffic areas, but still have the option of wasting less, everywhere else. Easy to clean and no leaking.