Is there any indication that Apple is taking these complaints to heart?
I suspect that the lack of updates may be indicative of Apple switching to an ARM based CPU for their laptops and desktop machine. If this is the case it probably wouldn't make sense for them to invest a lot in designing a new laptop around an Intel processor. It would also explain the delays since they would both need to get to grips with the hardware design AND provide a solution for running software compiled for x86 on ARM.
While they have done this before, the task is much bigger this time as there is considerably more software available for the Mac that would need to work on the new architecture.
Of course, this still raises questions. The first being how long it would take to stabilize the platform again. The second whether Apple will be sufficiently interested in the desktop/laptop market to deliver more consistent and meaningful product updates going forward.
If they are indeed going to ignore the desktop/laptop market the interesting question would be how this would affect the sales of their other products.
My guess is that if they manage to break up with developers, through inaction or otherwise, there is probably going to be a slow decline that nobody gets particularly worried about until it can't be compensated for with cheap sales tricks.