I don’t

I don’t understand why jews or christians or atheists refuse, even for money, to ask for proof the Quran is memorized. Muslims say Allah made the Quran easy to remember and I say it is impossible to memorize because the task is beyond human capabilities. The book is too long to be memorized therefore Islam is false. Nothing is lost asking for proof. Lives will be saved asking for proof. What is the reason for the refusal? .Thank you.