All that's been mentioned in the OP is quite attractive and looks simple when viewed. The same in reality isn't an easy thing to be done. I have a friend who is a Blockchain developer, I introduced him to cryptocurrency. He is from information technology domain. Now he masters me, and he tries to make me understand. I find it difficult to stand against his knowledge. From his experience on other domains of information technology different software he find it simple, while the same is unreachable for me. In simple everyone can't be Blockchain developer as some people think.
I also think that strong technical background prior to learning stuff about Blockchain is a must, or otherwise it would take a long time to learn even the basics. To be fair, the op does mention understanding various programming languages, and this kind of presupposes that a person is specializing in blockchain development after getting experience in programming. I don't think I'll ever become good at this stuff because I don't spend or plan to spend enough time on this. However, I think that potentially pretty much any average person can pull oneself together and become a professional if one spends enough time and puts enough effort into this.