Nothing personal, just a general comment ok? Kids skills now a days are bad with mechanics because you take them off what they seen and they just pop as a balloon. They know that a screw does this and that because they read it or because the manual says so and when an old bike shows up that is way simpler to fix they pop like a b/day balloon because they can't figure it out. In general bike components havent changed at all, is the same stuff again and again no matter the brand, and always the same issues, short chains, crossing chains badly or RD hangers that arent straight.

As for friction, thats the simplest and most effective shifting mechanism ever created, so simple that like 95% (making up numbers) of the riders cant use it because is too hard for them to move the darn lever just enough to make it work fine.