Ask HN: Any companies become successful simply by copying?

Very curious because the more I think about one of my own projects, the more it seems I want to make what this other company is making. Without disclosing any details, I briefly worked with said company, figured I could recreate most of what they had myself, and then actually own something of my own.

For reasons I'm having trouble articulating, it does feel wrong, though it's not like I have any trade secrets going on - one could look at the product and figure out how to build it themselves if one were so inclined. Don't startups have to be original ideas???