I think people tend read way too much into who the Captain is. Jones is probably going to play Slipper/Hooper regardless, based on his assessments of their play, so if they have a C on them or not it doesn't matter. It also brings continuity as opposed to changing the Captaincy willy nilly. These are people, so it is always going to be awkward if you just demote people in your organization on the regular. Alright, today Quade is the Captain. Oh he played poorly, let's make it Kerevi etc. It isn't a video game. If you take the Captaincy away from Slipper/Hooper now it's throwing shade on two key players. And for what? The radical difference that would be rendered by Nic White being Captain? Makes no sense.
In general though the Captain isn't that important. Ever notice that amazing Captains look amazing when they are also surrounded by a team of amazing players?
Kolisi plays with Lood, Etzebeth, Marx, Vermuleun, Faf, Am, and on and on. If the team sucked people will say Kolisi is too passive, doesn't work the ref well, doesn't motivate the players. If they win he's the stoic leader they always needed.
Richie McCaw was the best Captain in rugby history, right? He also played on the best team in the history of the sport, filled with all-time greats at almost every position. Surely a coincidence. If he was the Captain of Argentina in 2011 people would say McCaw cheats too much to be Captain, isn't a rah-rah guy, isn't physical enough for the job, and all kinds of assorted nonsense.
All Blacks Captains have gotten "worse" (McCaw to Read to Cane) simultaneous to the team and NZ rugby in general getting worse. Sam Cane as Captain on a winning team would be revered as the hardest player in world rugby, the toughest etc. Instead his team is (historically for NZ) bad so it must reflect him being a crap Captain. Couldn't possibly be the fact that they rely on aging players at key positions, have a bad coach, no consistent center combinations, no consistent fullback, inconsistent props, few impact forwards on the bench etc.