Cycling uptake starts with cycling infrastructure, very few people have a problem learning how to ride a bike.
It's definitely easy to learn once explained, and every enthusiast knows - but as a cyclist living near a popular bike route, I see a lot of casual riders who appear to have no idea how to use their gears.
The most common thing I see are riders with the cranked up in a high gear on flat land, and you can see them almost standing or straining to turn the crank. I cringe to think about the pain they are inflicting on their knees.
IME once you spend a few minutes teaching someone about their gears, they're usually shocked at how much easier and more efficiently riding is, and enjoy cycling much more.
Internal gear hubs make a lot more sense for casual cyclists -- they are easier to learn, they can be shifted when the bicycle is not moving, and they are far less likely to drop a chain during shifting than derailleur gearing. They are also better protected from weather and impact.
Almost all of the utility bicycles I've seen in Japan and Europe had internal gear hubs. I didn't see many people commuting on the kind of bicycles that American cycling advocates seem to prefer.
Same. Used to live near Greenwich Park and the number of people struggling up the hills around there in high gear was amazing. Even in low gear, I reckon they're a bugger for average cyclists.
Wait, is this not what you are supposed to do? How do you go fast then?
I hang out on some cycling subreddits and they commonly get questions from new cyclists that are totally clueless about how gears work. Some of them have it it completely backwards, ie start in a high (slow) gear and progressively shift down to a low (fast) gear as you get up to speed.
I always thought it was intuitive, but I guess I also got my first 5 speed bike around 7 years old or so, I can't really remember. I do remember having an RC car with 2 speeds Ang getting the principles pretty quick: gear one would accelerate faster but top out quick, while gear 2 had slower pick up but higher top speed.
However I would think straining hundreds or thousands of time on a ride vs a few dozen squats for a set has a much bigger potential for injury.
I'd also add it's not uncommon to see riders with their bikes unadjusted for their size, e.g. they might be in an already weird position with their seatpost too low.