I think it most likely a mix of all of the above, 125s as said are used to their limits a lack of experience and maintenance. It's like when I'm on the driveway weekly cleaning the bike, checking tyre pressures and checking chain slack. They don't tell you that you need to do more checks and hands on maintenance on a bike, there's no tin can to protect and hide it all. Even my neighbour keeps saying you are always messing with that! They just don't get it, then he drives off in his car with under inflated tyres!!! Less margins for error on 2 wheels. I think the main manufacturers and dealers need to champion good maintenance more. Let's face it there a market for basic classes to teach people the essentials and more