I find it odd, but many of the interpretations imply that the tree is so impossibly powerful that God couldn't reverse its effects. His only chance of foiling Adam and Eve was to prevent them from reaching it, as opposed to making the fruit poisonous. Or making the tree invisible. Or just destroying it with a snap of his fingers. Or just destroying Adam and Eve with a snap of his fingers. You know-- quietly murdering them and replacing them with replicas and threatening the angels so that no one would ever talk about it...
Then again, we're talking about a guy who struck a man dead for the sin of trying to keep the ark of the covenant from falling when the oxen carrying it stumbled while crossing a river. Insanely violent overreaction seems to be his modus operandi. Thoughtful and deliberate plans are a bit too boring for a book chronicling your exploits, I suppose.