Do you think US companies decide whom to hire for no reason? Not being available for interviews locally, not speaking English natively and needing a visa sponsorship already puts you at disadvantage compared to the local talent. If they still decide to go for you, there sure is a reason.

The reason is often money. Even with visa sponsorship. Perhaps $100k is too much, but ~$5k is too little.

The $100k fee basically makes it not about money. It's going to be more expensive to hire a foreign worker - meaning that if they're chosen over a domestic applicant, it's for a real reason, not just because they'll take a lower salary.