rrggrr is worried companies will say "1 year contract, $10,000 per day first week, $0 per day subsequent 51 weeks" and jump to the top of the stack as they're paying $10,000 per day.

Presumably the salary they bid would have to be maintained throughout the visa validity (e.g. three years for H1-B).

If the salary ever drops the visa is invalidated and becomes available for bidding by other companies.

You can require them to pay an average salary over the whole period of employment.

Most employment doesn't have a planned end point though

Why is a planned end point necessary? An average of say $100k per year isn't impacted whether you pay that person $50k for 6 months or $200k for two years.

It's to prevent you hiring an H1B for a one-month, $50,000 contract, then hiring them for a separate 11-month, $50,000 contract after. The company will argue the initial hire is a $600k/yr rate.

You could argue that they would get a one-month visa and top priority for that first month. The employer would have to go through the visa process again for the second contract.

They're already here, renewal is a completely separate process. The biggest hurdle is getting them off the plane, if they're employed, sponsored, and here it's much easier to keep them here.

Most visas do though, so it could be worked out.

Why do you need a planned endpoint?

In the UK, the immigration agency checks that you are still being paid above the minimum salary for a work visa. I see no reason why they couldn't check on this sort of thing.