The ability of English to easily incorporate loanwords is because it has lost almost all word flexion from Old English, with very few exceptions, like the plural marker "-s".

Because most grammatical markers are isolated prepositions, there are no problems caused by phonetic mismatches with the words to which they are associated, like it happens in the languages where a borrowed noun must fit into a declension pattern, which can produce phonetically awkward words.

While among the European languages, for English it is indeed the easiest to borrow new words, one can easily construct an artificial language that would be even better than English from this point of view, and which would remedy various problems of English, like the necessity of knowing separately a written form and a spoken form for every word, or the existence of a lot of semantic ambiguities that do not exist in other languages, or various difficulties to express various nuances using the existing modal verbs, or the too verbose methods for expressing certain verbal tenses, moods and voices.

Thus English does not really have any technical advantages. Its moat is the inertia caused by its so widespread use in the present, which will prevent any other language to replace it, regardless of how much simpler and better that language would be.