It's definitely a stretch to say we all run into these issues, but you'd be surprised how many beginner and intermediate-level developers don't know about this issue precisely because they've been insulated from it by frameworks.
There are plenty of situations where developers can find themselves dealing with insane JavaScript implementations and irresponsible JavaScript frameworks. While the article doesn't explain exactly what the issue is and which browsers it affects (leading me to believe the author himself doesn't truly understand these memory leaks), the recommendation given is a sound one.