I mean English has such a bizarro spelling system it may as well use pictograms. You might as well say "English will never be a lingua franca unless the English speakers overhaul their spelling". English is where it is because of the double historical whammy of the British Empire followed by American hegemony. Couple battles won or lost here and there and we'd still be using French.
Just as the saying is that a dialect is a "language with an army and a navy", a lingua franca is a language with the biggest army and navy (or trade/cultural influence). It has nothing, absolutely nothing, to do with the simplicity of the language, although simplified pidgins/creoles might develop as more non-natives have to learn it (hence how Latin evolved into French, Spanish etc). But pidgins/creoles tend to be localised adaptations and don't have the universal currency of a lingua franca - unless of course they develop into fully-fledged "imperial" languages themselves, as with English.
What does a learner of English need to be able to learn to write a word? 26 * 2 symbols, and a fair understanding of the most basic spelling rules to give any word a basic attempt at spelling. If you didn’t know the spelling of president, you could very reasonably guess your way through it (begins with a ‘p’, ‘z’s are pretty rare and I’d know if it had one, etc.) Contrast this with the modern state of China where actual teenagers have difficulties writing Chinese without the use of a computer because the written word is THAT vast.
I don’t see what your other examples have to do with anything…those are all languages that use an alphabet?
