This is the same problem as dribble - shit replicating shit and you end up with more shit. Mobbin is a bit better than dribbble - I’ll give them that, many good apps there. But hey … there are thousands of replicas out there so there’s a market for it. Copy and improve, copy and improve, there’s certainly a case to be made.
I don’t think Figma first designs are going away any time soon, but I suspect many will move straight into prototypes or fully exported apps. The simple stuff will be replicated but more complex b2b will remain a task for Figma.