I don't know why people are pretending that engines with treasure payload are rare.
It's still jarring to hear the pros have gone out of their way to avoid Silver and even Gold
I think all other things equal, Gold is avoided more than Silver in “pro” Dominion, though the recent influx of Gold gainers may have changed that a bit.
Silver is useful in the opening, so you often have one, and there are a lot more ways to gain Silver without buying it than to gain Gold. You need six Treasures to get Province using Golds, and eight with Silver; two extra stop cards is often worth it if you have a way to gain Silvers but not Golds.
That said, there are plenty of boards where treasure is a big part of the payload. They’re not all that uncommon - but often you can do better these days, and you generally want to minimize the reliance on Treasures.