I fear software/driver obsolescence will kill the viability of my maxed-out 5,1 for work (video production) sooner rather than later.
At that point I’ll have to suss out whether the 7,1 makes financial sense compared to moving (gasp!) back to PC.
Until recently Apple’s QuickTime-wrapped Prores codec (and its dominance in video production) made a move to PC not really viable. But now that even Prores is transferring over to the more universal .mxf wrapper, that opens up the playing field a bit.
That said, if a moderate spec (i.e. “affordable”) 7,1 can provide enough beastliness to churn through high-end colour-grading and editing for the next 6-7 years. Then it’ll probably be worthwhile.