Poker is in a sense just like school.
On the lower limits, some people get by fine by "slacking", thus not studying a whole lot and not putting in much effort since they naturally pick up on things that enables them to beat the game. Just as some barely have to study to get C/B in school. Others have to put in way more effort to reach the same results.
At a certain time, we're gonna come across less bad players and more players who has just an easy time as us getting by with no effort. Either that, or people who simply outwork us. The higher limits we play, the more true this becomes imo.
There is sooo much to learn about poker, and to get to where Sapheal is you need to put in years and years of countless hours of studying and playing. Even then you are not gauranteed the same successrate.
Poker is like starting a business of your own, or getting a college degree. Whilst you educate yourself or whilst your company is growing, you most likely won't be able to survive on it as a income.
Only once your company grew big and successfull enough, you can start making a living off it. And your degree won't earn you any money until you've learnt enough to master the profession and you're given a job.
It's completely up to you how fast your company (poker) grows, and at what successrate. Variance may give you a boost or slow you down, but the learning part is completely up to you. It's completely up to you to outwork your competition. It's up to you to develope a mindset that will allow you to play poker for a living. It's up to you to seek out all the information you're gonna need.
By no means am I trying to discourage anyone, it IS possible to make a shitload of money with poker, it's just not gonna come easy. 
If you dedicate yourself to poker the way you would dedicate yourself to a college degree or a business, you can certainly make a career for yourself!
Chop chop, lots of work to do!
