Sorry, but this is not true: there are numerous example of natlangs dramatic
prescriptive changes (and on scale that has nothing to do with a few cmavos
more or less, with a population size that has nothing to do with lojban
community present size, and regardless of an existing voluminous existing
corpus), that were consciously accepted by users on a short period.
The reasons are numerous, but strive to improve the tool, I mean the
language. Indeed there are voluminous linguistic studies done solely
on that aspect (for instance, there is a french multi-volume books by
Hagège and Fodor 'Voies et destin de l'action humaine sur les langues',
but I am not sure of an english version). BTW, this is a fascinating domain
of linguistic as it has very often political and social deep implications.
Very true, but your point about numbers invalidates what you are saying.
To use the example I'm most familiar with, Turkish went through a
period of rapid and largely planned change in the early years of the
Republic; the aim was to standardise grammar, replace Arabic and Persian
loan-words with "pure" Turkish equivalents and adopt Turkified European
scientific terms where no Turkish equivlent existed. It was largely
successful due to the fact that in many cases they were simply replacing
the Ottoman court language with something that would bemore
comprehensible to the Turk in the street, partly because they had a
dirigiste state, and partly becuae they had a user base of tens of
millions to play around with. The same does not apply to conlangs with
a user base of a few thousand (if that). A Turkish citizen has to speak
Turkish, and if he/she wants to do official business, then that means
using whatever kind of Turkish the Türk Dil Kurumu deem appropriate. A
speaker of a conlang is more likely to say, in the immortal words of
Eric Cartman, "Screw you guys, I'm going home."