Has that not been what a senior SWE is? You’re making it sound like engineers need to be asked to implement features rather than contribute to design. At my company, if you are not coming up with new features or applications, your days are numbered.

Depends on the organization and on the SWEs. I do share your understanding, which is making me unfit for organizations, where the authority over "what" is firmly held by POs and the whole vertical on top of them.