Of course there’s always reasons. Teaching it to children isn’t really a solution: you’d need to know where words come from before reading them correctly, and also many people don’t learn English as children.
Phonetic languages do borrow words from other languages too, they adapt them to their own language keeping the pronunciation (the only example coming to mind right now is the Czech for sandwich, sendvič). English could do that just fine being phonetic was a goal
You would know where words came from based on the way they're spelt. That would let you know how to pronounce them. It's the exact same thing people do now we just do it without thinking.
The systems at work in English are not nonsensical like people like to parrot. To say it's not phonetic is just wrong on every level as well.
Frankly I'm fine with the historical oddities that have led to modern English. If non native speakers have issues, that's tough luck for them!
Phonetic languages do borrow words from other languages too, they adapt them to their own language keeping the pronunciation (the only example coming to mind right now is the Czech for sandwich, sendvič). English could do that just fine being phonetic was a goal