I rather suspect that McLaren have agreed with Honda that almost all their efforts this year will go into building next year's car, and that only developments which are relevant to next year's car will be pursued. For example, improvements to the front wing should carry forward to next year's car.
What they haven't done is to repackage the power unit and cooling system components, which is where the biggest gains this year could possibly be made.
So I don't think Honda will be too unhappy. They'd actually be more worried if they saw a big effort going into the current car.
Yeah it is strange, McLaren have put almost no packaging work into this years car when they quite obviously run the least optimized solutions for engine cooling and sidepods.