Not sure I agree with that. It's not difficult to notice one has "nai", other don't. Also when you read it in actual sentence you can immediately notice that something is wrong when you choose the wrong reading. Subsequent words don't add up. I am not saying confusion doesn't occur. I'm just saying it's not as big as people are painting it.
if it's 大人気ない it's probably childish, but if it's not in that context, it's probably very popular
You need to finish reading the whole SENTENCE to be able to pronounce it