The issue with this list is that it will only reduce spammy notifications for non-spammy companies.
As long as some amount of people keep engaging, these companies will keep spamming. It’s similar to email marketing in that for most industries ~25% open rate and ~3–5% click rate is considered good. They only need that small percentage of people to be engaged to continue to piss off the other 75%.
The main issue as you point out is that there is no clear, user-visible way to manage notifications. For iOS at least it’s all or nothing at the start. For most apps you want some notifications (new LinkedIn Message, new Twitter DM, etc.) but the all or nothing switch places the burden on the user to dig into settings and switch on or off the specific notifications she wants. Even worse are the apps that don’t provide these options and lump in their marketing push notifications with their transactional ones.