What it takes to retire early or at least be in a situation where a job loss, or other difficult life situations wouldn't effect you all that much is known for ages. Acting on it is just a totally different thing altogether.
And this is not just restricted to money. Nearly everything is like this. You could have a habit to read everyday, do push ups and eat healthy. You just have to do a little of this everyday. But most people struggle to keep up.
Success is doing boring things. Unfortunately since being boring is unattractive, some people actively avoid succeeding.
And it's also why everything seems to coincide; those who can maintain physical fitness often have the wherewithal to maintain financial fitness, etc.
It really does come down to "we know what we have to do, but it's too f**ing hard and/or tedious".
And arguably not worth doing. Tomorrow may never come -- you could get hit by a bus driving home today.
Studies show that a lot of poor people spend money immediately because their lives are often crazy uncertain and trying to balance and pay debts -- which they may never pay off -- doesn't get them anywhere. Blow the money on a new xbox now, because even if they pay the rent today they probably won't be able to stop eviction next quarter.... but at least they have an xbox, and can take that with them to the next flophouse.
If you live on 100% of your income, you are doomed, you can't save anything.
If you live on 90% of your income (ignoring market returns for simplicity) you "earn" one year every 9 years or so.
If you live on 50% of your income, you earn a year every year.
And if you somehow got down to 10% of your income, each year you worked would be nine years you wouldn't have to.
This math works with 0% return (or a return matching inflation only).