A “good enough” conversion certainly might put someone off, but then it’s also possible they wouldn’t have achieved any better. But equally a poor port might motivate someone to try harder, just as things like the original Bubble Bobble or R-Type ports lead to people pushing harder.
I don’t think it’s enough of a reason not to do it. If someone has the passion for something enough to do it, chances are they’ll do it anyway. And, as people get better with AI tooling at least a few of those will probably lead to amazing conversions of things we’d never see otherwise.