Hi! As I wrote this reply then I decided you are right. If there is nobody with substantial stake who opposes a particular change then it is non-contentious. Examples of this include the Ethereum Homestead and Ethereum Metropolis-Byzantium network upgrades, various Ethereum emergency bugfix upgrades, and at least one Bitcoin emergency bugfix upgrade. I expect the Zcash Overwinter and Sapling network upgrades to fall into this category — nobody will seriously oppose them.
This is the lower right-hand quadrant of
(from A Future Friendly Fork; note: written January 2017, before the Bitcoin Blocksize Debate moved from the upper-right quadrant to the upper-left quadrant. Also by the way I saw that there was an ETC presentation at a recent Ethereum conference, so maybe the ETH-ETC split is migrating from upper-left to lower-left!)
If there is an economic interest that would lose due to a change, and they think they can potentially benefit more than they would lose by opposing it, then it is contentious. Same with if there is a social faction that is ideologically opposed and is willing to fight. Then we’re on the left hand side of the picture, where there will be two blockchains, although I still think we might be about to hit the lower-left quadrant — a Friendly Fork — instead of the upper-left — a community schism like BTC vs. BCH.
Anyway, I guess this means you are right and I was wrong — as time goes by the amount of support for an ASIC-Friendly Zcash blockchain does grow, but not because of the increased hashpower (which I think has next to no effect on the way this kind of thing plays out) but because of the increased economic commitment!