You switched from a company that's slow with updates to the company that's slowest in updates. Will they release Lollipop? Most likely. When? Maybe before the summer, maybe not. (Remember, the latest Lollipop release, 5.0.2, is a bug fix - that probably still has lots of bugs. I don't know why anyone would want to risk his phone to alpha test something for Google for free. Wait until there's a fairly stable version, then start complaining. Until then, update to the Material Design version of all your apps - that's about all you're going to get over 4.4.4.)
Don't judge updates by Google's announced release date. Once Google releases it, the manufacturers have to modify it to work on their phones - that takes months. (Android is written to run on the current Nexus phone.) Once a manufacturer releases their version of the current Android to the carrier, the carrier makes its modifications. That can take months. A difference of 6 months between the Google release and your carrier's release isn't slow, it's normal.
(The reason Apple can release updates so quickly is that they're writing, at most, 3 versions - North American GSM, world GSM and CDMA. They don't announce the "release date" until it's been written, alpha tested, beta tested and ready for release. It's like "forecasting" who's going to win the 1948 presidential election. All the many months you hear rumors of an impending iOS release, it's actually being worked on, tested, debugged, etc. There's no delay between "it's done" and "it's released" except for the one Apple inserts to make you think they work so fast - you'd never believe that they wrote it overnight, so they can't announce that they're going to be working on one on Monday and release it on Tuesday. But it takes just as long for Apple to write a new version of iOS as it takes Google to write a new version of Android.)