It is a consolidation effect. The top monthly car in Europe is typically a compact car selling about 15K units. There is just not anything in the Model Y's league in terms of size/price in the market right now. A base Y in Germany is 54K euro. An ID.4 seems to be about 44K, but is significantly smaller. Now that production is fully underway it takes demand from a lot of other classes. That has been part of the sales success in the US. Prior brands of Tesla owners in the US range from Toyota to Mercedes.

It’s an overall brand rating. X and S are now such a small portion of Tesla sales that they probably don’t factor much into the ratings.

People don’t buy it for the cost savings. As much as people harp that Tesla isn’t a “luxury” brand, a big part of its market is taken from customers who would otherwise buy BMW, MB, etc.

Initial quality that also includes cosmetic defects can be very different than overall customer satisfaction where Tesla excels.

You will find a really negative narrative here, but it’s a really great car. The size is very functional, the tech is great, it’s very comfortable, and range is very high. Tesla still tops the industry in customer satisfaction.