They're expensive, and ones with as many gears as a derailleur system are hideously expensive. Folks worry that they won't have the gears that they need for hil

They're expensive, and ones with as many gears as a derailleur system are hideously expensive. Folks worry that they won't have the gears that they need for hills. Also, I think the bike makers are timid about marketing them -- an entire line of bikes might have exactly one with a hub gear, on a bike with "city" styling. I've got a couple of bikes with old Sturmey Archer 3-speed gear hubs, and they're utterly bulletproof. I've had each one open exactly once, when I got it and wanted to make sure it was in good condition before putting it on a wheel. Plus I was curious. The other thing in my opinion, though I love hub gears, modern derailleur systems with a zillion gears aren't all that bad. Especially with indexed shifting, which we've now had for decades. They're exposed to the weather, but most people don't ride in bad weather. Since you mention hybrid/city, that's my category. I use my bike for commuting to work, shopping, and weekend recreational rides. I'm in no way fast nor competitive, so the weight and efficiency issues are secondary for me. But also, the 3-speed is a sweet spot where its efficiency actually rivals derailleurs.