You can definitely feel it when doing subtraction on a Curta, there's significantly more drag involved in it both because you're generally adding a larger number so more teeth interact but also the wave of the carries going around. However the low digit doesn't have to power all the carries though on a Curta because all the carry does it shift a gear up that then interacts with a single tooth (or 9 during subtraction) on the drum that performs the carry for the next digit up.
There's a whole page of Curta info [0] and a 3d simulator [1] where you can see how similar the setup is and some of the ingenious tricks to fit all of the functions of this machine into a little larger than a grenade sized package.
Yes, as the number of wheels scales up, powered carry becomes necessary.
Another mechanism that's been used is sort of analog - differential gears, with two inputs and one output. Race track totalizators used that to add multiple unsynchronized inputs. Here's one from Adelade.[1] The machines were huge and heavy, but reliable.
(It is a tradition and a contract term in the gambling industry that gambling equipment companies are strictly liable for errors. As a result, that industry builds unusually reliable equipment. GTech once mentioned in an annual report that they paid out about 3% of revenue in error payments.)
There's a whole page of Curta info [0] and a 3d simulator [1] where you can see how similar the setup is and some of the ingenious tricks to fit all of the functions of this machine into a little larger than a grenade sized package.
[0] https://www.vcalc.net/cu.htm
[1] https://www.satadorus.eu/x_ite/yacs_2_0/yacs_2_0.html