Not only did Apple and Google divebomb their sales, but Nokia's own hardware was plagued with bugs and comparatively inadequate features, like small displays and slow CPUs.
MS would later re-sell Nokia to HMD in 2016, who still release some feature-phones, including ones running an "S30+" OS that has nothing to do with Symbian.
I have one of these running KaiOS and it works surprisingly well. It also seems to be immune to battery life degradation (it works just as well as it did when I got it) and in general has been rock solid. I think in the almost six years that I've had it, it has spontaneously rebooted once and other than that it just works. It is simple, has buttons (no touch screen), has an earphone jack and is so solid you can drop it and the chance is larger that you damage the thing it lands on that that you damage the phone. It still looks like new in spite of being in my pocket together with keys and other stuff. I'd buy another in a heartbeat if this one ever dies but I suspect it will just keep on working.
MS would later re-sell Nokia to HMD in 2016, who still release some feature-phones, including ones running an "S30+" OS that has nothing to do with Symbian.