Especially wild if you consider health insurance is tied to the employment.
3-6 months notice period is standard in EU countries. Unless you are sabotaging or always drunk there are no ways they will fire you quickly.
At Will employment cuts both ways.
Company fires their employee at 8:30AM on the spot: Employee is now without income and likely health insurance and his ability to pay rent, buy food and merely exist might now be in jeopardy.
Employee quits at 8:30AM on the spot: Company is at worst set back a bit until they backfill that job. At best they don't even notice. Unless that employee was some keystone that held the whole business together, there is no existential threat to the company.
Ps: without at will system you can simply stop showing off at work with the same results.