The OP likely is talking about tech because it's what he knows. But generally, as a Canadian who has hired immigration lawyers and knows the US immigration process well, you are never getting into the US to "mow lawns, pick produce, and clean bathrooms"... almost all the long term Visas require an advanced degree (4yrs of university) or equivalent in experience in an industry in high demand (doctors, engineers, etc).

You may be mistaking illegal immigration with legal.

That’s true of certain visas. There are a variety of different visas.

I grew up next to an orchard that almost exclusively used Jamaican guest workers to pick apples and other fruit. Same thing with horse tracks, etc. There is no farm operating at any significant scale that isn’t using migrant labor, mostly legal.

The OP seems to be talking specifically about the H1B visa, which is for speciality occupations. Produce pickers need not apply.

There is a website that lists them all. You’d be surprised to see how many H1Bs get paid less than $30k/yr.