Remind me: which company has just been sold for peanuts after trying the WP strategy?
Specifically, for $12.5 billion, minus $2.4 billion for the set-top box business, minus $3.4 billion in net cash, minus $2.5 billion for tax assets. Actual cost to Google: $4.2 billion.
Compared to Nokia: €5.4 bilion = $7.2 billion.
Nokia was the market leader in smartphones before they went WP. They were larger than Apple and Samsung combined and then some more. Motorola wasn't a big factor in the smartphone business. Google bought them for their patents, certainly not for their mismanaged smartphone strategy. So, Motorola went from 0% smartphone market share to roughly 3% with Android. (Nothing to write home about, but you can't blame this on Android.)
Nokia on the other side was at 34% when they decided to go all in on WP, and look where they are now: 3%. Nokia's fall is of historic proportions. Motorola's fall doesn't even come close.
Nokia's mistake wasn't in killing Symbian for smartphones in 2011. It was in not killing Symbian in 2009 or 2008. But it's hard to give up that market share and start from zero.
In cases of disruption, high market share is actually a disadvantage, because you stick with your existing product longer than you should.
As for Nokia killing Symbian: To publicly announce a year before you actually ship the next product, that your current products are now obsolete - huge mistake! I don't think there is any dispute on this.
But we digress: I strongly believe that if you do it right there is money to be made as an Android vendor (don't forget those emerging companies from China, Huawei, xiaomi,...), but there is no money in WP. Nokia did a brilliant job with their Lumias, but they just won't sell without the right OS.
Telco relationships and distribution channels are necessary but not sufficient. All the other phone makers had telco relationships and distribution channels, too. Didn't help them compete against the iPhone.
What got them some traction was that they threw out their old smartphones and started over -- 2 years before Nokia finally got around to doing it. That 2 years made all the difference.
There is an argument for Nokia ditching Symbian and keeping it secret. This assumes it could've been kept secret. A change of that magnitude was bound to leak out -- for example, a Symbian engineer quitting the company in disgust and telling the newspapers.
Disruptive innovation is called disruptive because it turns your assets into liabilities. For example, your factories and distribution network used to be valuable because they gave you scale that nobody else had. But now, they just cause you to have higher fixed costs than your competitors. The classic example being US Steel when the minimill disrupted the steel business.