I haven't read the thread in its entirety, so I apologise for any conclusions I may jump to.
I think I see both sides of the story here pretty well. I understand where the OP is coming from, but to answer your question in the simplest way possible - You can have your own space, almost whenever you need and want it - there are just sacrifices that will inevitably come with it.
Although our stories are different, I decided I too wanted my own space, I wasn't happy at home etc. So at 15, I decided to leave home. I had enough money in my pocket I had saved up from odd jobs the 6 months before to pay a months worth of rent. I found a student house to share, I lied and said I was 18 and at uni. I enrolled in the 6th from in the area and took 5 A-Levels (most kids were taking 3) - By moving out I knew my parents would not support me (If I needed the help, their suggestion would have been to move home). Knowing this, I had to get a part time job to live. I applied to every possible place in the city - and found a job within a week. There was no minimum wage for under 18s then, so I earnt £2.05 an hour (This was 11 years ago).
To be able to pay rent and live, I had to work from 6am until 8am every morning - walk an hour to college as I couldn't afford the £1 bus - attend full time classes from 9-4 every day - walk the hour home - then do 6-11pm 3 days a week - I then had to work 8 hours a day every Saturday and either 8 or 16 hours a day every Sunday. This gave me enough money to pay rent, buy school equipment and eat. That was it. I couldn't buy clothes, electronics, nothing. Did it suck?? Absolutely - It was miserable - BUT - that was the price my own space cost me. Instead of complaining about it, I got on with it, I studied and got 5 As in my A-Levels and went on to University, where I continued to pay myself through.
It absolutely made me miserable for those two years, but I was too stubborn to give up - and that hard work and stubbornness - allowed me to make decisions that meant I was able to live alone from 23 onwards, with stability and comfort with enough disposable income to afford what I wanted. It then allowed me to move to the other side of the world, to continue a job I love, buy a house, more than one car and everything else I own.
Moral of the story - Your own space comes at a price. It is more often than not, a miserable price - but its all about personal balance. Sometimes a little misery enables you to move to great things. If things are hard now, push through them, learn from them, and figure out how to make them better in a couple of years time, so you never have to go through them again.