For me the rot set in even before Elop.
Nokia were never really bleeding edge, but they made good reliable phones for most of the 10+ years I owned them, right up until the last couple of years when the lack of updates to known bugs (or allowing the carriers to customise, and in effect blocking bug fixes) crippled Symbian phones. The N95 for example, was actually a good phone if you jumped through all the hoops to reflash the model number to generic Euro so you could get the updates direct from Nokia. Unfortunately Joe Public didn't know (or what to know) this, so he was stuck with the carrier branded firmware the phone arrived with. Unfortunately the OTA update ability of the N95 seemed to coincide with Nokia developing a "It's okay, we know it's got bug, we can ship it, we'll fix it OTA later"... Which of course they couldn't if you had a carrier branded phone. For some reason, even non UK carrier branded handsets had a weird UK firmware, which caused any firmware updates to be delayed just getting over the border.
Things were not learnt (by them or me!), so when the N97 arrived with a touch screen lashed onto Symbian, and an incredibly generous 32gig of storage plus microSD, it had horrendous bugs. Unfortunately even flashing to generic Euro didn't help this time as Nokia had got your money, and didn't seem to give a hoot about the bugs any more. One of the more major ones for me was the terrible GPS. Various hardware modifications to the antenna failed to improve things, leaving the conclusion that there were serious hardware/software problems deeper inside.. Support dried up before the mobile contract finished, and I even managed to get censored on the Nokia support forums for "disrespecting Nokia" for pointing out that if they didn't support customers they would soon have nobody to support, and therefore no job!
Oh how I laughed 6 months down the line when Elop arrived and proceeded to dismantle the company from the inside.
The N97 was the last phone I bought in a contract bundle, and also the first I abandoned before the contract was over. It was replaced by a phone purchased outright..
It was Android, and so was my next one, and so is my tablet, and my old tablet which has been handed down to my mother. Both my brothers now have Nexus 5's... My mother is still using an old Nokia N70 I gave her many years ago, but she wants a better camera for the grand kids... Not 100% sure which one I'll buy her, but it'll be running the same OS as the tablet she has got used to.
"Treat them mean and keep them keen" is not a good motto for business.