You can't sponsor an illegal. To get an H1B Visa you have to be... documented. So, no. There is no "incentive" to hire an undocumented immigrant to replace a citizen and then pay them so little they're on SNAP benefit.
Prior to Trump, it used to cost $2,000 to $5,000 per filing. So, every time you wanted to bring in an H1B visa worker, each petition was $2,000 to $5,000. And that wasn't guaranteed. If the petition was rejected for any reason, to re-submit it was another fee. That's the fee the employer has to pay, not the visa holder.