You must take into account attrition rate. Not every novice becomes a expert. Say in a given field, on average, each person spends 10% of their time as novice,

You must take into account attrition rate. Not every novice becomes a expert. Say in a given field, on average, each person spends 10% of their time as novice, and 90% as expert. If only one in ten novices actually grow into experts, in the overall population most man-hours are spent at beginner level. Novice teachers don't outnumber experiences ones, but students surely outnumber teachers, by a large margin. In a market that still didn't achieve steady state, like programming, some of the people that didn't made it through may end jumping ship to more beginner-friendly alternatives, that end with more people, more libraries, more learning resources, et cetera. Eventually the network effects will cause even the expert ponder over switching sides to get better libraries. Think how Python ate Perl lunch, despite the swiss-army chainsaw power of the later. Today there's probably much more Perl programmers than in the 90s, but yet we can't deny the language lost mindshare.