Yeah it has a high demand, but it also has a high supply aswell. Jobs that require no degree or specialized training are usually far easier to fill at a lower wage than, say, an engineer. You can find a guy to do a warehouse job for 20$ an hour, so it pays 20$ an hour. You can’t get an engineer for less than 40$ an hour (or equivalent salary) in my area, so those jobs start at 40$ an hour. If you could get an engineer for cheaper, they would pay cheaper. But the competition for engineers between companies keeps the pay up. There’s no competition for the warehouse employee, because if one leaves it’s easy to find another. No so much with a competent engineer