ELI5: Why has the English language changed over the years so that words which are written the same aren't pronounced the same, yet phonetic languages haven't.

Let's be clear here - English has lots of loan words, which are responsible for much of our weird pronunciation. That's not what I'm asking about.

I read this article today, and was intrigued by this paragraph:

Professor Crystal found that 96 of Shakespeare’s sonnets contained lines that no longer rhyme. Sonnet 154, which begins “The little love-god lying once asleep”, once tripped off the tongue but modern readers struggle because “warmed” is paired with “disarmed”, “by” with “remedy”, “perpetual” with “thrall” and “love” with “prove”. “In modern English it’s a mess. In original pronunciation each couplet works perfectly.”

It seems that in Shakespeare's day, English was much more phonetic than it is today. But since then, the language has changed, with the pronunciation of different words going in different directions, so that the language is now the mess of mixed phonemes which we love!

I understand the process by which this has happened. But... why has it seemingly not happened to other languages?