The last Zune devices were released to the market in 2009. The last version of the Zune software was released in 2012. (Notably, the music store is still operational, although it is rebranded in most places outside of the Zune software.
There was never third party software support for Zune devices, so it's not like that was "pulled."
The Zunes were always a technically superior option to the iPods of their day. The thing that killed the Zune was the fact that people wanted a music player integrated into their phone, and the Zune wasn't a phone. The Zune HD, which didn't really have apps, was released to compete with the iPod Classic, which also didn't have apps and was also killed by the rise of Android and the iPhone.