Sure but even without factoring in additional factors like unions and labour laws that is solely a question of negotiating a deal between an employer and an employee.

Getting a significant raise is not unheard of, in particular when switching jobs, and a 4 day work week is basically the same.

Basic negotiation strategy suggest that "labour shortage" is the right time to ask for this.

Some companies have extremely fat margins and regular employees may very well feel that some of that money is better spent on their salaries than dividends, C-suite compensation or stock buybacks.