I agree with this argument but don't you think the decline of Arabic was due mainly to European colonilisation. After the fall of Abbaside Caliphate,Arabic had been neglected by The Ottoman ,English and french empires. When Arab countries have become independent,their leaders have used Arab dialects to promote their power and interests on the expense of classic Arabic. Consequentely,Arabs themselves not just the foreign powers are responsible for the decline of Arabic as a science language. To make it scientific you have to use it in communication not just between Elites but between ordinary Arabs.
Some people believe that classic Arabic is a dead language like Latin,used only by experts.
This is true. However,Hebrew was also considered as a dead language like Latin before the Second War. I believe the success of a language depends more on the will of politicians than the scientific communities. These Arab dialects do not interest me because their use is very limited. On the contrary, the vast majority of Arabs speak the colloquial dialect on a regular basis.