Knowledge work in the US (especially tech) is on another level entirely. You would not be treated this way in retail, service jobs, or at most employers AFAIK (this also depends heavily on the state). As far as I know most employment contracts are at will, and they can fire you and give absolutely nothing. However, for some reason all these tech companies are being very generous with layoffs. Possibly they don't want to burn any bridges for the future?

According to https://webapps.dol.gov/elaws/faq/esa/flsa/007.htm

> There is no requirement in the FLSA for severance pay. Severance pay is a matter of agreement between an employer and an employee (or the employee's representative).