It was removed from MySQL in 8.0 because it wasn't very useful. MySQL query caching does exact matching on the query string and any row update to a table used for a given cached query nukes the entire cache. So it's only useful for a small set of niche use cases where tables are essentially static.

I assume this is a bit of a joke, but query caching at least was not good in 5.5-5.7, so it would often be disabled. I don't know how 8 performs.