Two things that I've observed that may lead to the Sonic's early demise are low fuel prices, and dealers that don't stock many Sonics. I have three fairly large Chevrolet dealers nearby; one has two Sonics, the others have five each in their inventory, and of those, they are poorly equipped. On the other hand, there are ~ 60 Cruze or Malibus at each dealer. I guess if one wants a Sonic, it would have to be ordered. When there are incentives or discounts available, they apply to in stock vehicles, further reducing the sales of the Sonic. Apparently there isn't sufficient profit margin in a Sonic for the dealers to keep them on hand.
EDIT: I just noticed that chevyoffers.com shows a picture of the Trax on the Sonic page! At least it does for me. That sucks.
Right..we Americans want bigger and larger cars...we need a 4500 lb vehicle to go buy groceries..oh and it better have surround sound and 4k video to get us to the grocery store.
Sad note, the Chevy dealer I was at only had 2-3 I could see on the lot in the back and non out front... But they had a ton of Cruze's.
The other part of the equation is the profit margin on the Sonic. I'm sure dealer thinks it's a waste of time when they can double their profit on something more expensive.
Too bad though, I love driving my RS.