You will never have enough time to be really good on every part... except you have no private life. I can develop "everything" too, from Assembler, many Basic d

You will never have enough time to be really good on every part... except you have no private life. I can develop "everything" too, from Assembler, many Basic dialects, VisualBasic, C, C++, PHP, JavaScript, CakePHP, Typo3, Node, Java, Android, MySQL, MongoDB, Apache, Nginx, to different CloudServies (S3, Rackspace) and many things i forgot in my 25 years programmers life. I can use them all, but i not assume that i can use them all like somebody who is specialised and thats the difference. Yes, full-stack developer are needed, because they have an overview of many things, but in detail a specialised programmer is meaningful. And your are right, 85% is for most customers more than enough, but the really good payed jobs are not from 85% of this customers ;-)