They have. Two other commenters have weighed in, but neither mentioned the replacement I prefer - newsblur.com, good enough that I'm a paid subscriber.
I liked NewsBlur but for some reason switched over to InoReader. I wish I could remember why though, but I haven't been using feed readers for quite a while... Either way, both are good services but somehow I always wished I could GReader back.
Digg Reader works pretty well for me. It's bare-bones, but that's all I really need.