Is that true? Is there not any laws protecting the employees or setting time limits for the notice and the actual end of the contract?
You cannot fire someone for membership in a protected class (race, religion, sexual orientation, etc) or participation in protected activities like reporting an employer’s violations of the law, but it’s difficult to prove intent in such cases.
There are exceptions for unionized workplaces with collective bargaining agreements. Employers in those situations cannot fire employees without “just cause.” Google R&D is not unionized, however.