What if there were tariffs applied to importing laborer or using offshore contractors?

That wouldn't do anything to address any supply shortages of workers for certain skills but would at least level the playing field for citizens looking to get into fields like tech, nursing, medicine, and more.

If you tax remittances at 50%+ I have a feeling that suddenly many of the incentives for the H-1B workers themselves would change for the better.

If we tax remittances at 50%+. I'd buy so many BTC call options.

And then large companies can just set up entire offices overseas - all of the large tech companies already have large offices and subsidiaries overseas.

One major firm I worked at built a giant campus in Mumbai, I believe it was. The huge office building here in the US was sold off and was just recently torn down to make way for I don't know what--a whole lot of lower paying jobs, if anything. Their footprint here in the states is now laughably small. It's beyond ridiculous that such a stable employer for decades would now look like this.