I think both are true. I have far too many plugins. Many never
even get a passing on, but stay in the collection.
There are 2 factors....the Engineer, and the plugins...
But a brilliant Engineer can take even the crappiest of plugins and produce
a masterpiece...I liken it to the "Tone is in the fingers" argument...
because a brilliant Guitarist can take a cheapo First Act Guitar,
and create brilliant sounding material with it...
As with all things it's highly subjective. But, above all, it's the Engineer
(or player) that ultimately is the "Real" ingredient.