1. The USA has a shortage of appropriately qualified pilots.
Fixed it for you.
2. That is debatable, if foreign pilots are not sourced what would happen to the terms and conditions of the USA pilots?
It's not complex, but the regional model will only take a certain level of remuneration before it implodes, some say it's not far off this, when/if this happens, what will happen? Will it be rolled into mainline with a fleet of 75 seaters? Who knows, but the jobs won't completely disappear.
3. The Australian Government would never let foreigners in if there are qualified citizens unemployed.
With the greatest of respect, bullsh!t. The government will do it's utmost to lower wages in almost every sector. All you need as a sector is a plausible story decrying the 'labour shortage.'
I seriously doubt there is an unemployed E190 pilot in the States, not unless that pilot chooses unemployment. Australia however.