The most bitcoiners arent skilled people, with that said, isnt an easy task to reach since some signatures are paying around 0,04bitcoins and combining captcha, faucet or any other way that can allow to earn bitcoin will become an hard way to get those income but inst impossible, is just hard work.
The sources which you mentioned above are not the only sources of earning bitcoin but there are a number of other sources also which can make a person able to earn about 1 bitcoin in a month or two suppose he start a blog and start to invite people to that blog then in that he will not need a special skill but only will provide some news at some interval and when the traffic is increased he will be able to earn about 1 bitcoin in a month or two.
Sure blogs may let you earn something into some time, but you need a lot time and dedication to make your blog a sucessfull and with some quality traffic, i do see several websites connected to bitcoin that are into the top websites, soo sure make some can allow you to earn even more but you need to work into it alll days.
Anything that let you earn money is like that. Think about it, if you didn't go to school at all, you wouldn't get any job. We've been working our whole life to become a productive citizen of the society. You've been working on your capital for a long time already. Any job, investments even, would have some requirements and all those requirements would be about you.
Take making blogs for example, it's a work-based job. If you aren't good enough in posting articles and/or if your not updating about the new stuffs enough, you wouldn't be qualified. Maybe somehow you can be still qualified for keeping up the blog, but you wouldn't have the same earnings as someone that possess all the needed requirements which are traffics, talent on posting and frequent updates.