It's always the same with that kind of question.
If you have skills, use them. Maybe with an online job that pays you bitcoins, maybe with a real job where you earn fiat.
When you have no skills, well, it's gonna be hard. Money comes not out of nowhere.
There are a lot of people out there without any skills all wondering how they can earn money.
Those who have found a way won't tell. They don't need the competition.
Yes no one will disclose their secret of earning money as they don't want that others should also get benefits from it but if you don't have skills then you can always develop and learn those skills by working on it as there is nothing impossible in this world.
Here I fully agree with you. No one will want to give out the secret with which he manages to earn 1 Bitcoin for a month or two months. This is good enough money, Therefore, everything is always kept secret.