If the rate of murder exceeds the rate of entrants for any meaningful number of suppliers, that might not be the case for the purposes of mitigation (which to be clear, is all you're going to get, never eradication). However, what you say may be true, I only cannot say it with certainty.

You would probably kill more people that way rather than making it a death penalty for use. The other problem is enterprises that make money like this can easily corrupt the police and politicians. Since users don’t make money from using they’re not able to pay off the police.

Any solution that is predicated on uncorruptable police and politicians is not going to work. I wish we didn’t have such corrupted police and politicians so we could have nicer policies but we don’t so we can’t.