This wouldn’t be a good idea at all because it’s not just reads that dictate whether or not a story gets on the shelf. You have to go through the retention and the rubric. The only reason I’ve mainly seen for people advocating for this is to help small creators. But how would banning them result in any real positive effect for smaller authors? It would just remove people’s eligibility, and it might cause some people to boycott contests because they think it’s unfair.
I think the mindset and idea of preventing people from entering stems from the idea of contests being competitions. They are competitions, but it doesn’t always have to be about winning the contest. You can always end up on a shelf, build a fanbase from it, or just have fun. Not that many people win every single contest they’re in, but they still get recognition for the work they did. In my opinion, that’s what matters most to me.