Of all the things that can go wrong on a product page, a missing price is one of the strangest, because it's not a bug in the usual sense. The page loads fine, the description is there, the image is there. It just never actually answers the one question every single visitor has, which is how much this costs.
Why it happens at all
Nobody sets out to publish a product page with no price. It usually happens sideways: a variant gets added without its own price set, a bulk import maps the wrong field, a product briefly goes out of stock and the price field gets cleared instead of hidden. None of these throw an error anywhere. The page just quietly renders without the one number a shopper is scanning for first.
It reads as untrustworthy, not just incomplete
A shopper who can't find a price doesn't usually assume it's a technical glitch. They assume the store is hiding something, or that the listing isn't actually for sale, or that something is broken and they should be cautious about the rest of the page too. That reaction happens in seconds, long before anyone would think to contact support about it.
It's easy to miss if you're not looking for it
A store owner scanning their own catalog tends to look at the parts that are visually obvious: broken images, awkward layout, typos. A missing price on an otherwise normal looking page doesn't jump out the same way, especially across a catalog with hundreds of listings, which is exactly why it tends to survive unnoticed for a long time.
This is one of the plainer checks PagePolisher runs on every product page it scans: is there a real, visible price on this page at all. Simple to check for, easy to miss by hand, and costly enough to be worth catching before a customer does.