mhmm?...but then you would need a squire for every archer then, bad logistics. And whats to say that javelins could not be massproduced in a similar manner if needed?
Well, that's how they fought. I'm just sharing ideas for your consideration. Servants and arms and baggage trains full of semi- or non-combatants were a big feature of all armies and late medieval ones especially.
For professional mercenaries, whether they are pikemen or crossbowmen or lancers, the "train" was often family or close people. Your sons, brothers, wives, whores, boys, whatever. They depended on you for money so they came anyway.
Mass-producing javelins: as long as the workshop is consistent in what it does there's nothing stopping mass production, but that's the whole issue. Arrows don't need to be nearly as consistent in execution to work AND they are actually easier to make consistent.
Javelin-makers would basically be specialist tradesmen if they were to mass-produce the kind of javelin that could challenge late medieval armour.
I mean, it's a possibility, but there probably are better choices.
Consider the arbalestier, coming into pointblank range at 50metres, if he shoots through the steel armor and shield, good for him...but if he doesn´t the javelinguy is in his face 20 seconds later and throws his javelins, in a rapid pace.
A javelin man carries 2 or 3 shots, maybe 6 at most, plus armour, plus has to be in great physical shape.
I can see them as expensive specialists that could join other forlorn hope teams in disrupting advancing pikes and archer lines. I mean...you can think of a niche where javelinemen can fit for sure but you have to consider, would they given that Europe had little javelin tradition for a long time and good alternatives were widely available?
That's all.