That's not just a Samsung issue though. And even when a manufacturer takes care of the lastest updates, you still got to wait on the carriers if it's a branded device.
True, but when you haven't got a carrier handset and your still left in limbo it's annoying. Especially when Samsung were touting lollipop themselves as far back as October last. We were promised December, then January, then Feb and now we're mid March and the vast vast majority of Note 4's are still on 4.4.4
When you consider original lollipop framework was delivered to third party manufacturers as far back as July / August it's getting pretty ridiculous.
But yes this is a greater android issue in general, and one of the reasons I like having an iOS device as well.