I think that's how it looks from the outside, but people I know who have bought these cars look at it different.
They like the attention to detail of mercedes and the quietness.
They like the attention to detail of bmw and the performance.
(not sure about audi, don't know anyone well who has one)
But this move sort of pulls back the curtain between the marketers in charge at these companies and their view of the customers. "they are price insensitive and will pay more without worrying".
But really - you don't want to piss off a first-class customer. it's easy to get under their skin if you treat them with disrespect and they remember.
All of those cars are essentially badge cars - i.e you pay more for the badge that shows that you have money and are able to pay more for the cars. Nobody buys those cars because they are better at commuting than other cars. So subscription services is natural for this type of market.