"Starting early", super important!
"Getting lucky", yes - both in time and in income - striking gold is not much worth if you can not step up on the possibility - and sadly, for many, having kids or a ill parent, or loosing a steady income is to big a obstacle to tacle... Meaning, you might not have that many a year to live that, wild, frivolous, entreprenourish life...
Yes, to say the least... I do not know what paved the way for all aforementioned programmers put after reading about Carmacks work in "Masters of Doom" I'd say focus is extremely important... And at least myself is extremely bad at it - there is always 10-ich projects going on... If you want success today I think being extremely specialized is a must.
It's about knowing where you want to go, what you want to achieve, and be able to focus enough to go there. Vision + Execution.
For me focus is at the same time "fast and slow".
You have the focus on the long term vision of your career, products etc. That means, yeah, probably choose between your 10 projects. But again, it depends the goal you set yourself concerning those 10 projects. If you're a pragmatic OSS commiter ("I commit the changes to this lib' I really need for my main product"), then 10 projects is okay.
Then You have to focus, during your day to day work. Where do I head with this feature? What do I want to achieve? What problem am I trying to solve here? Did I think about all the edgy cases? Did I test everything? Is the code better now than before? etc.
