Usually the work of an engineer is done when its done and is not speed up by people hoping for it to be faster. Also usually engineers like to get their work done and move on to something else interesting. At leasts thats the attitude i got towards that.
i am no expert in this area so I only got two datapoints: 1) sony needs X months to build AOSP, 2) jolla needs about the same time to build a reliable port. As long as there is no competitor to jolla who does the same thing, we can just assume that this is just how long it takes. All other claims just sound very unfounded to me without data backing them up.
Also it looks like no manufactor wants to build the same device for many years, thus I do not really see obvious room for improvement.