You can earn bitcoin using anything, it depend on your creativity and skill.
For example, you have high speed connection or huge internet bandwidth, you can offer leech, proxy or download upload using your internet and they pay you using bitcoin.
I do agree with you. Currently, I am a freelancer on the internet and I do a lot of things to earn money both in bitcoin and paypal. It depends on your creativity and how good you are. If you are good enough, you will earn good money