They cannot do that during one period. They can only suggest such change and then the next elected government can approve it. This way the people will always be able to vote against such government.
And I really doubt any party would suggest any drastic change on this topic.
Just a sidenote.
The fact that it's a fee instead of tax means that the government cannot change how much money SVT should receive.
This means that journalists are not controlled by neither politicians or companies.
This means that we have real journalism and free media.
And I find that awesome =)