People look back fondly at Strikeforce's roster simply due to what so many of those fighters went on to do in the UFC. If they never fought in the UFC, people would think of them like they do current fighters in other orgs.
What many fans won't admit to is that they only care about the UFC names. If a fighter doesn't have that affiliation, they are thought lesser of. It's just the reality. It's why these companies are never going to compete with the UFC.
It's why PFL buying Bellator is meaningless. You don't care about fighters in either company now, nothing is going to change with a combined roster. People just watch UFC fighters slumming it in the minors. It's why you have people still talking about Bellator's roster being old. It's because they only care about the former UFC names, so it's all they recognize.
It's why fighters like Eblen come out of nowhere. They didn't care until he fought Mousasi. If that fight never happened, so many of those fans still wouldn't have a clue who he is, even though people like us realize how much more impressive his fight with Tokov was. That's because Tokov doesn't exist in their world either.