How would you account for the fact that for many words, there isn't a consistent pronunciation rule for it at all? For example, I would guess that 50% of English speakers are non-rhotic.
It's also decentralized - there's no authority to tell the English-speaking community how to spell things or how to say things.
I think these are both advantages that outweigh the phonetic inconsistency.
Assuming we wanted to make English a phonetic language, then your question is kind of moot: phonetic means we need to pick the pronunciation rules for phonemes, which would make other ways to pronounce these phonemes incorrect. Some of currently-correct english would become incorrect english.
> For example, I would guess that 50% of English speakers are non-rhotic
Note that accent isn't really what people talk about when they complain about pronunciation. The problem is that there's no mapping from letters to phoneme in any english accent: laughter/slaughter, draught/draught, G(a)vin/D(a)vid...
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
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!