I'm really not expecting you to address anything
. I'm just responding to posts and giving my opinion.
I don't think that having separate rates for singles and partners is the answer though. We consume the benefits of living in a civilised society as individuals (whatever our domestic arrangements) so we should, IMO, all pay tax. I would exclude children, the sick and disabled, and probably have a maximum number of years when this was expected, although there would have to be a way to stop people from simply deferring their obligation until they would never pay it.
I don't know - I'm not an economist or a politician, and it is much easier to say what is not fair than what would be better. I don't think it is fair for people to be able to opt out of taxation by opting out of producing goods or providing services - to me that is a double whammy when it comes to being part of society - but you can't get blood out of a stone.
As has been pointed out, however, we may well be on the cusp of an era in which it can't be earnings that attract taxation, so new ways to pay for things (if that's the economic theory to which you subscribe) will have to be found.
Family don't pitch in and help

. I also agree with biglouis that the work ethic is changing. That may be just as well, given that AI is likely to pull the rug from under the way work and reward has been structured since the Industrial Revolution.