You can rent a property I think, if you can fulfill the landlords criteria for rental. You can only get married with parents consent, you can decide for yourself from 18. Voting there was some discussion about, not sure the reason 16yr olds were denied the vote in the end. I think you can't work at 16 now either, you have to be in education until 18. The age for alcohol being 18 is possible health reasons? IDK. You can drive a moped at 16 but not a motorbike or car until 17.
So it's a transition age from childhood to adulthood. No idea why it was done like that. Wasn't always so.
Maybe something to do with child protection? We've stopped sending children up chimney's too. Parents and teachers no longer have the right to carry out corporal punishment. Education being compulsory is because children have a right to it, meaning poor families can't send their DC out to work to boost the family finances. Parents now fined for taking their DC out of education to eg go on holiday.
It works both ways too. If you were adult at 16 you'd have to pay for you own college/6th form education, currently the government pays until you turn 19. If you commit a crime and are imprisoned, it's a children's prison not an adults one, before age 18. If your parents kick you out you get more help from the council than an over 18 single homeless person would. Your age gives you some sort of priority I think. Lots of people being informally supported and still treated in a childlike manner by parents as they go through university. Don't be so keen to shake off the shackles of childhood. It comes with benefits too.
If you're really sick of being a child, get yourself into a situation where you're ready to launch into full on adulthood when you turn 18. Instead of drifting along in extended childhood like so many do. Make the most of the free education to get skilled in a trade and/or qualified for a career, work as much as you can and save to pay your way through university without so much debt as those who haven't saved up. Or use your savings for a second hand car enabling you to work further away or for a deposit on a flatshare/some basic furniture enabling you to move out of the parental home. Get a good reputation for yourself at whatever job you do because it'll really help you get your first adult job if you've already proven yourself.