You took one sentence out of context and ignored many others. If there are real problems with those programs they should be improved. If employers are simple ignoring them because they're a hassle, and it's always been easier to just hire illegals, then those employers should be dealt with under the law.
But like everything in immigration enforcement, the guest worker programs have been ignored because those laws aren't enforced either. People just hire illegals and get away with it.
The government could change that, just as it could enforce the border and many other things related to illegal immigration it chooses to ignore.