If I'm answering the question from my perspective, it's because I'm 17, I have no income and I can't drive
Not being able to drive needn't stop you. You might be able to get a ride from someone else (family, friends) or take public transport. Not to mention the possibility of learning to drive.
As for income, you don't need it to organize a user's group. And if you did need it, you could try to get a job to earn some. Participating in and organizing users' groups is a good way to make contacts which might lead to job opportunities, by the way.
At the moment, I have a terrible, terrible portfolio/resume, so getting a job isn't on the horizon yet, but if I do I'll be learning to drive pretty sharp-ish
At this precise time in my life, one of the most important things in my life is getting code written for a portfolio
I'm in the middle of the sticks at the moment, but hopefully to a town with a train link to London, which would be amazing if I could pay for trips to London for meetups :D