I think this depends a lot on the country and how much economic opportunity there is. In some countries- like china in the past, for instance- you couldn't start a business without favor from political elites.

If you live in the USA, made $10 an hour (just a proxy for "minimum wage"), you net about $18,000 after taxes, or $1473 a month. IF you can find a room to rent for $400 a month and spend $300 a month on food etc, that leaves you about $750 a month to save. That's $9,000 a year or $153,000 over 17 years (the time it takes to go from 18 years old to 35 years old.)

That's assuming no growth in your income or returns on your savings over that period.

What's worked well for me personally is, whatever my income, I've tried to live like I had half of that income.

This is easy in some places, harder in others. Impossible in New York City (I think.)

This is also why I think that Remote work is a huge opportunity-- people could live in cheap places while earning an income from companies in expensive places with high value businesses.

EG: Programmers moving to Butte Montana and working for Bay Area Startups.