> Isn't it simpler to just shift our times, for example in the summer start to work at 9:00 and in the winter at 8:00?

You make this sound so simple, but the "our" you're referring to is "hundreds of thousands of employers". Yes, it is simpler to change the time than to convince every single employer to voluntarily shift their working hours in tandem with everyone else. Even one would be practically impossible: everyone would have to sit down and adjust every single meeting by an hour.

"Meeting's at 10am!" "Wait, is it 10am before or after fake-DST?" "I don't remember, did you change it?"