There are many different ideas out there if you care to explore the, and it's not always about excluding groups based on arbitrary factors like age and gender. Honestly, something along the lines of Starship Troopers. The book not so much the film is my line of thinking.
Certain forms of public duty earns the right to citizenship and therefore the vote. Military service just for one example.
When people have no real skin in the game, they shouldn't have a right to vote over other lives. If you want to shirk responsibility for the world we live in fine, but it means you don't get a say. Rights should come with responsibility, and not be a one way street.
One great example of failure of rights/responsibility is the NHS. We certainly wouldn't have an NHS crisis if people didn't abuse alcohol, cigarettes and shovel cake down their throats. The "right" to healthcare certainly isn't being matched by individual responsibility. I think society as a whole needs to have a serious think about how things are run.
The last two years have shown large numbers of people are happy and content to be told what to do and what to think, some even seem to prefer it to freedom. I don't really mind that, but the fact they influence political discourse, and can vote over my life does bother me.
And to be clear, I'm not sure I would ever be a voter, so I'm not trying to be superior. If a smaller better filtered voter base choose better leaders, I wouldn't need to earn a right to citizenship or the vote.