> tapping into your creative mind and finding unique ways to supplement your income
One of the things I do like about MMM is that there's none of this handwaviness - it's much more straightforward: get a good job and be frugal.
It's great if you can come up with a good alternative source of income, but it's not easy and not for everyone.
The goal then is not necessarily to retire, but to just get to a point where you are working for yourself and supplementing that with existing savings + a frugal lifestyle. That's basically what MMM/Pete is doing now with his blog. That is, I believe, how a welder/car mechanic/McDonald's employee can retire early.