This is kind of correct, at least for people that ride little and aren't aggressively using a motor's full potential when they are riding. I think your cost for replacement is drastically off unless you are riding the cheapest POS possible. You're correct that chains aren't expensive to replace, but when you start swapping out full cassettes and CNC main drive gears it can get pricey even if you can do the work yourself. Mid-drives can apply far more torque to the chain and gears than two humans can produce on a tandem... that means more wear-n-tear. It also means more outright failures. That's a big reason why so many mid-drive riders don't use their full gear range, especially on multiple horsepower mid-drives, choosing to rely on that readily available torque to help grunt it out rather than swapping gears. There are a couple of ways to fix this... the first is to get a bike that can use a Gates belt drive and never worry about the f***ing thing again. Unfortunately not an option for me. The other is to ditch the rear gear cluster for an internally geared hub like the Rohloff Speedhub. Fortunately, that was an option for me. There is still wear in the chain and the rear gear. I have gone through maybe 15 chains and 7 two-sided rear gears in the last 5 years. I'm getting close to years riding (5-7K miles) on a single chain and one side of the rear gear... when they wear they can be flipped over and used backward. All this wear is on a chain that never has to jump gears or flex over an inch from side to side. People that want to ride an ebike more than just around the block or around various local parks have to understand that maintenance will be necessary. How necessary depends on how well you do your research and how much money you want to invest. Regardless... it will be more than a "drop in a bucket".Stay safe.
