In retrospect this seems like a silly concern given the Windows Phone market share and how obvious the solution was:
> and once shared-data plans reach critical mass, Verizon and other companies will have an active incentive to encourage the use of messaging services like Skype. More Web-sent data requires a beefier data allotment, after all.
Wasn't that already the case?! I didn't really follow plans available in the US around 2012-2013, but in East Asia and Europe, making subscribers pay more for bigger and faster data packages on LTE is exactly what every carrier was doing.
Regarding Samsung phones, of course Samsung had a good relationship with carriers and would typically be more willing to bend to their will, for instance by delaying and doing staged rollouts of firmware upgrades. However this isn't the main reason here. Samsung was absolutely dominating the Android market, being pretty much the only player making comfortable profit margins on the hardware. On the other hand, Samsung's leadership understood that there was nothing easier than moving from an Android phone to another, and that eventually a big part of the cake would be eaten by Chinese OEMs. Samsung worked hard on building its own brand of phones with One UI and its predecessors. The leadership absolutely hated the fact Google forced so many apps being preinstalled on certified Android phones. Hence people complaining about the number of duplicate apps seen as bloatware, sometimes rightfully so.
I don't think Samsung was afraid carriers would take offense at something as ubiquitous as OTT messaging. Case in point, I had coworkers working on ChatON, our own version of iMessage/FaceTime. This was a flop obviously, which is a bit sad since I believe Samsung had a real chance to acquire KakaoTalk around that time.