Updating phones fast will not happen, unless they can make something happening that didn't happen in the last 4 years.
What devices should they bring to these carriers? Windows Phone devices are certainly not more exciting than the current Android hardware. The 630 is laughable and even the Lumia 930 that's not even released yet features specs that you can get in a Sony Z1 Compact or in a Nexus 5 for a much lower price. Also, Microsoft much rather releases more Android phones it seems.
The Xbox One's momentum? The "okay, Kinect was a failure we don't sell as many consoles as we should"-momentum? Windows Phone's Xbox integration? What does that even mean, the games with a green name tag? Xbox games on Windows Phone have as much to do with the Xbox One as Xbox music...
What are the special synergies between Windows Phone and Windows 8? Onedrive? I really don't know, and I use both.
What I want to say: I don't think things are as easy as this article wants to make us believe.
1. Updating to Windows Phone 8.1 can be made easy by Microsoft, it just depends on how the carriers will react. One way would be to give carriers full control over OS + firmware updates, but in parallel, offer OS-only updates to users directly. I imagine that would be an OK compromise considering that Nokia is no longer the sole maker of WPs.
2. Yes, WP lacks compelling devices for carriers to pick up. As it stands, carriers are more enthusiastic about low-end Windows Phone, they do better on the market than their high-end counterparts.
However, Microsoft did have a shot in offering a compelling mid-range device for the carriers: Take the Moto G with LTE and add PureView (i.e. an updated version of the L920's camera) and micro-SD slot.
By having this device start at $299 off-contract and cheap/free on-contract, and with a variety of colours, replaceable shells, etc, Microsoft can position this as a comfortable choice for carriers. It wouldn't surprise me if most or even all major carriers pick up said mid-range device. It's a safe bet for the carriers and still compelling to the market (given the price and the value offered by a good camera).
As for high-end, if carriers are not forthcoming in a given region, Microsoft can sell to users directly off-contract and unlocked, or perhaps tie the phone to an upfront purchase of 2 years worth of Xbox Music/Gold, SkyDrive, Skype and/or Office 365 subscriptions. The latter option might be tempting to enterprise customers.