We have fairly new carpet, and it’s prone to getting those marks from heavy things left for a while, but it doesn’t even have to be heavy. All it takes is a relatively light box to leave an impression that won’t come up with vacuuming.
Nothing works at all on the marks left by really heavy stuff, I’ve even tried wetting the spot and using a coarse brush. I’m betting that the carpet is medium quality at best.
You could try it, but with care – some steamers get a bit fierce, and some carpets aren’t going to react well to that.
I have seen ice cubes recommended as a solution to this problem – place one in the indentation and leave it to melt. I haven’t tried it, but it can’t hurt to give it a shot.