They sell just fine. McDonald’s in the US is ideologically against them. I think I posted about this before. I was in a situation where I got to discuss it with a high level executive. They don’t want it no matter what the consumer demands.

The store manager we were buying ours from said no one was buying them there. But then again I don't recall seeing any marketing there that they even had it. We only found out through the app and after looking around for one. I imagine McDonalds wouldn't want something that makes their other burgers look 'unhealthy'. I bet their profit margins were smaller too.