""big box" hardware store."

The low prices are the result of the low quality.

So does a high price automatically indicate good quality? Is there anything else to look for?

'So does a high price automatically indicate good quality?"

No, but to make the item at a low price something has to give.

Chrome is expensive to do correctly requiring under-plating for many metals, and a thick enough layer to avoid pin holes.

Plated brass has similar problems.

Pin holes in the plating allow the (often) steel base material to rust under the platting. Thicker platting has less chance of pin holes, but costs more to apply.
Solid brass eliminate the whole issue (but you could not afford something made of solid chrome).

There is a reason that most of the surviving old chrome plated items made it. Thick chrome correctly applied.

The thinly plated items rusted and have been discarded.

I have a chrome plated soda bottle opener form the 1950's that looks as good as the day it was made (steel opener mounted on a steel plate and covered with a chrome plated box to catch the bottle tops).
It is heavily chrome plated, and while there was light rust on the interior side, the plating on the outside is pristine.

As the other poster points out, the process has to be done correctly. Anything in a bathroom is exposed to constant and extreme humidity so it has to be done above and beyond what would be acceptable in another environment.

Sadly, ALL the current bathroom light fixtures are mass produced in China and done the cheapest unsupervised way possible. An issue also is that your "other" bathroom fixtures that you say look good are chrome plated BRASS which takes a lot longer to rust than cheap steal. However, it's much more expensive material. Having to deal with over 100 bathrooms these issues can get expensive!

I bought two fixtures for my two bathrooms from Wayfair they both rusted, and I am discarding them. And they were expensive.