I bet you don't have a lock on your front door either. Besides you need incremental increases to ever be able to reach 100% security. If you shoot every single idea down because it's not 100% secure you will not get anywhere.
This is what is frustrating about the cryptographic community. People should not be discouraged to try new algos and techniques otherwise how is anyone new that isn't already 'in the club' to gain knowledge? Of course new developments need to be audited and peer-reviewed but this sort of immediate dismissal is not constructive.