You said it yourself, those offenders supply talent to other companies. Many roles simply won’t be available to citizens because they’re filled by H1B abusers.
Yeah, I think the abusive companies like TCS and Wipro should be shut down. But the other companies generally pay pretty fair and use this visa system pretty normally, and they do see a shortage of qualified talent. I saw it myself as an interviewer. TCS and Wipro have a completely different quality standard (if you can call it that) and everyone knows it, plus they are cheating