The previous couple of reforms I believe were successful because of communists' ruling style. The first one was dramatic, it removed several letter from alphabet and did a bunch of other changes. People who run away from communists in 1917..24 continued to use old grammar for decades.
> The difference is that countries speaking the language agreed on setting common rules, with the goal of making official what is already becoming standard by daily use.
There is a trouble with that. The standard by daily use is to follow official spelling. Pronunciation could shift sometimes, but spelling is fixed. Any changes in spelling (even official ones) feel as blasphemy. Some people could overcome this feeling, but the most could not and want not.
That makes trying to regulate it more reasonable.