I don't think there is a delay in the release. I think LG started working on MM for the V10 either in November or December.
With the V10 launching around the time of MM's official launch, LG had no choice but to ship with Lollipop because they didn't want to delay the launch of the V10.
I think they thru MM to the back burner until later so that they could focus on the launch of the V10 and getting MM on the G4.
I think if the V10 had launched a month or two earlier, we would see MM by now, or if LG had waited a month or two later to launch, it would have shipped with MM. But obviously they needed to start selling devices.