There is no reason there shouldn't be 10 bans
Whether it's a captain on each team banning 5 or one ban per person, there is no reason.
"Entire champion pools get banned out" Learn more than 10 champions. It's not that hard.
"They could ban out every meta pick" Stop being a meta following sheep, and again, LEARN MORE THAN 10 CHAMPIONS.
"One single role could get banned out" Firstly, that means the other 4 roles are completely untouched, which will almost never happen. And I can still easily list 10 champions I could play in my main role.
And before anyone asks,
. That is more than 10 and not the only champions I can play in the jungle. If you really main a role and are good at it, then you can play more than the same 2 champions.
There are 123 champions. We get 6 bans. You can ban out less than 5% of the champions. Consider that half are nowhere near ban worthy, that puts it at 10% of 'ban worthy' champions. And with 10 bans, there would only be 8% of the champion pool banned, with around 16% 'ban worthy,' or if you only consider a small portion ban worthy, then upward to 32%, IF you consider only 1/4 of the champions to be worth a ban at all (not saying OP, just annoying enough to merit a ban).

Wow look at all these melee ADCs. Not to mention the melee
supports who can't harass melees at all.
all work in the adc position as well
all can harass well from the support position and have abilities that can keep bruisers off your carry against a double bruiser/tank lane.