"Jobs that Americans could fill" is not what people are talking about when they talk about H1B abuse.

H1B abuse is when you do things like pay people the minimum salary as required by law, and THEN set up some illegal contract with the employee that says that if you leave before 2 years, the engineer has to pay back 10s of thousands of dollars.

Or another common thing that happens is that the same company will submit a person multiple times through shell companies, so that the person has an unfair advantage in the lottery.