Most of this simply has to do with lack of disruption. Almost all sites tend to add clutter over time because new things need to be added and some stakeholders

Most of this simply has to do with lack of disruption. Almost all sites tend to add clutter over time because new things need to be added and some stakeholders don't want old things removed. Sometimes the only way to get clean new design is to start over. My guess is that competition has been less fierce and/or has been won (rigged?) by incumbents more often than it has been in the US, leading to slower iteration and acceptance of less-than-ideal design by consumers. Enterprise versus consumer apps is the same story - lack of disruption and consumer choice leads to decisions that make sense only to the middlemen.