Notarization is a completely automated system to scan for malware. It has existed for many years
Once tooling catches up, in theory, developers don't have a contractual relationship with apple anymore, except to get notarized.
The devices belong to the users apple sold the hardware and licensed the software to them not app developers. They could charge the users but obviously this would be a terrible idea.
Getting notarized will either directly require payment of the platform fee or will force the use of the official tools which will mandate that.
That is absolutely a win to the common people. And it’s not like other companies taken a hit - they can either stay on the AppStore and have their finances go through their “taxing”, or create an alternative store and find a proper monetizing strategy. They can calculate what makes sense, but it makes it hard for Facebook/google to exercise their network effect for creating a new app store at the expense of users.