"...many Chinese people consider the creation of Chinese calligraphy to be one of their primary contributions to civilisation..." - is this really true?
Anyway there are no reasons to oppose the natural process of more advanced languages displacing the less advanced ones, apart from political (avoiding cultural assimilation).
Chinese calligraphy carries far more artistic dimensions compared to non-symbolic languages. My grandmother has accrued such a beautiful Chinese font style over years of practicing calligraphy and being reporter on battlefields. Her ink writings/letters have been passed down to my parents and taken good care of as family treasure brought overseas. Being Chinese British I still occasionally use them as copybook to practice. Even though all everything about her was told as stories, her handwritings, those strokes & circles, speaks a decisive, brave and clever woman.
Each character needs to be written in balance itself. Like architecture all characters itself has a firm pillar stroke and together they also need to fit into structural of the whole paragraph. Positive or negative, aggressive or passive meaning can also be expressed by same strokes but sharp or round in the right place.
Chinese script is arguably superior in many respects, and it provides a whole platform for "creating language" rather than just script.
Forgetting how to properly write by hand is not just a problem for those writing in complex script, although it's exacerbated by complexity. People relying too much on spelling correctors feel lost without them and make mistakes, people also go months or years without writing by hand and struggle when they have to.
There's a natural process of writing more with technological aids, which by the way favours Chinese script as it retains its strengths and loses its drawbacks (there are extremely fast Chinese input systems). It may well happen - seems to be happening - that moderately skilled handwriting becomes as rare as professional calligraphy is now.
There are plenty reasons to oppose the natural process of advanced things displacing less advanced ones. Cultural assimilation is not a political reason, it is an emotional reason. Many Chinese people regard calligraphy as art, so naturally they'd be uncomfortable with a newer generation not being able to perform it.
I think western society has the same feeling towards cursive writing, although it is much easier to obtain the basic skill of writing cursive western characters not many people are still able to write it in a beautiful fashion.
Without telepathy, the diversity of languages is still important and there is unlikely an ultimate language more advanced than the rest, just like there are so many programming languages of all kinds. If Chinese is displaced then the new one is highly possible of the same kind.
Anyway there are no reasons to oppose the natural process of more advanced languages displacing the less advanced ones, apart from political (avoiding cultural assimilation).