That would be a massive over-reaction. Look at what would happen when the next corrupt Democrat president or governor wants to get rid of somebody: he'd get a corrupt AG and some corrupt drug enforcement agents to plant drugs on the person he wants to imprison or execute. A couple years later that person is on death row or forced to plead guilty to avoid a death sentence. The law can also be used to oppress political opponents.
Execution for meth dealers/manufacturers. It'd be a kindness to them and everyone else. They've given up their humanity.
Using your logic, since every law can be abused, there should be no laws or punishments whatsoever. I don't agree.
It's akin to the logic of "people will do drugs/have abortions/commit murder anyway, so no use having laws against such things.