From a logical standpoint, standardising language certainly works as an idea, but humans are not so logical! The history of language is that of languages merging and diverging. It kinda depends a lot on who you want to talk to at any given time.
It's not clear that language is inseparable from culture; there are arguments to be made that language shapes thought (see "1984" for an extreme thought experiment!), and culture might well be shaped by the network effects of such frameworks.
As for cultivating a world wide culture, perhaps we can already see it happening! And perhaps global language would follow. A few years back there were great claims made that in a century we'd all be speaking so-called "Panglish", the sort of global pidgin that would emerge from mashing lots of languages into English. Maybe ... maybe not. If there were a "standard language", chances are it would be at least partially based on English, and supplement local languages. But it depends entirely on whether everyone really cares about understanding each other, to the extent of learning a common tongue.
I agree with most of what you have written except this part:
but humans are not so logical!
I don't believe there is anything illogical about the diversity of languages.
No different from the existence of multiple,types of programming languages.
Sometimes I wonder if this kind of notion of what's "logical" is a confusion of short-term instrumental thinking with what is actually successful in he long run. In many biological systems, for example, diverse evolutionary strategies play out in competition and exchange with one another with the end result that "life" more generally persists and grows in complexity on a grand scale. Humans seem to have an inverse tendency towards projecting uniformity wherever possible, with the end result being limited models that subsume as much as possible and then collapse under an unexpected pressure (the structuring of Western economies being the most obvious example of this). I wonder if we'll ever develop some kind of meta-logical approach whereby we intentionally foster diverse, but somewhat isolated, strategies and then experiment with varying levels of exchange to arrive at better outcomes.
It's not clear that language is inseparable from culture; there are arguments to be made that language shapes thought (see "1984" for an extreme thought experiment!), and culture might well be shaped by the network effects of such frameworks.
As for cultivating a world wide culture, perhaps we can already see it happening! And perhaps global language would follow. A few years back there were great claims made that in a century we'd all be speaking so-called "Panglish", the sort of global pidgin that would emerge from mashing lots of languages into English. Maybe ... maybe not. If there were a "standard language", chances are it would be at least partially based on English, and supplement local languages. But it depends entirely on whether everyone really cares about understanding each other, to the extent of learning a common tongue.