I don’t think the GB would ever voluntarily lose membership or contract their presence if they had any other option. If there was any possibility of growing and remaining afloat they would pursue it full on. The idea that you can have a controlled decline of the religion is probably a bit like trying to have a controlled fire in a barn full of hay. Anyone stupid enough to attempt it will soon have a pile of ashes for their trouble. Because loss of morale can take on a decisive downward trajectory of its own and declines can compound before you know it. Credibility, once lost, can be difficult to impossible to regain.
Plus as former Witnesses I think there is a tendency to overstate the strategic prowess of the GB. If it looks like they are presiding over an incompetent almighty mess, then that’s probably because that’s exactly what it is. Arguing that it’s really part of some ingenious strategic plan is just another variety of exceptionalism akin to the pedestal of “faithful and discreet slave”.