More and more companies are shifting to 4-day-workweek model. At least I have seen the trend on my LinkedIn feed. Is this really happening? Is that the future?

That's a privilege only for first-world countries 😉

In India 5 days a week is already a privilege. Most industries have 6 days work-week.

Yes , i have also seen , i think in Europe countries they are trying for 6 months to check if that is beneficial or not .