My monthly expenses are in the $1200-$1400 range.
I'll let you figure out how I can save 50% :)
Oh! Me! Me! I know! You... earn in the $2400-$2800 range!
On a slightly more serious note, one thing that gets us all closer to our 50% (or whatever) target is that we've stopped digging ourselves into deeper holes. Over the next five years, most of us will earn more money, through raises and promotions, especially if we bother to improve our qualifications. If we own our homes, we'll build up our equity and reduce our mortgage interest payments. We won't be buying any more dumb shit, or paying any credit card interest. We'll pay off any vehicles we own. We'll learn more and more DIY skills, and get better at almost everything we do (shopping, cooking, growing things, making things, repairing things, understanding people). We'll mature, and realize we no longer need some things that we currently pay for. Our current (and growing) savings will pay us returns (interest, dividends, rent, whatever). And we'll run into options that we can't predict (a swell new work colleague who offers carpooling, a sweetie that we can share our home with, a big transfer or promotion, a side hustle, a neighbour who shares tools or skills). So many of us can turn a current savings rate of (say) 25% into 50% or more, just by Not Fucking Up.
Edit: Did some simple NFU math on my own situation, and over the past five years my pay's gone up about a thousand bucks a month, and my expenses have gone down by a little more, just through shit happening (basic mortgage payments and renegotiation, child support reduction due to kids growing up, better cooking and shopping and fixing things, realizing I like staying in hostels). As a result, I've gone from saving about 22% of take home to about 39%, with another 10% of my gross going into the company DB pension. And the only really mustachian choice I had to make in there was to avoid lifestyle inflation.