Let's imagine that there is an auxiliary language that takes 10 words from every language on Earth. Such a language would in fact be profoundly unfair to speak

Let's imagine that there is an auxiliary language that takes 10 words from every language on Earth. Such a language would in fact be profoundly unfair to speakers of minority languages today because it would deny them access to the largest markets of the world. The English speakers would keep their knowledge and access to global markets while the Finnish speakers would gain 10 words of English. Woopty doo. So a language that takes words only from the top 5 languages would be better, yes? Because it teaches minority speakers more words from more important languages. But even still, what does that give you if you learn 500 words from each major language and the grammar is a bizarre mash up of totally different languages? The most "fair" language would be the one that gives the minority language speakers useful and meaningful access to the most influential language family "at a discount". Picking from one family would allow one to distill the grammar and vocabulary, giving the student truly useful and applicable information if they decide to later branch out into natural languages / dialects. In today's world, the most influential language family is by far Indo-European (for better or worse). And it just so happens that this language family is the easiest to synthesize and join back together, although there's nothing stopping others from trying to make a Semitic auxiliary language or a Sino-Tibetan auxiliary language, etc.