"A flexible work schedule is an alternative to the traditional 9-to-5, 40-hour work week. It allows employees to vary their arrival and/or departure times." (U.S. Dept. of Labor)
So, starting at 9am instead of 8am on Monday and Wednesday and every other Friday is the big work/life changer? Or leaving at 3pm instead of 5pm three days a week makes all the ills of work/life balance all better? Are those changed hours universal and always aligned with personal/professional responsibilities?
"A hybrid work schedule is a flexible work model that combines remote and in-office work. It lets employees work from home on some days and from the office on others. Workers don't need to be in the office all the time, but they're not strictly telecommuters either." (Asana)
So, working from home/remotely v. in the office on some days fixes everything? Which days are best to work from home/remotely v. in the office? Is it the same mix every week? Who decides? 
"While a typical full-time schedule may have you working Monday through Friday from 8 a.m. to 5 p.m. for a total of eight hours a day, five days a week, a four-day workweek includes four 10-hour days. Some employers allow four workdays of eight hours each." (Indeed)
So, a four-day work week transforms the way people work/live by requiring them to work four days a week instead of requiring them to work five days a week? But what if the employee only needs to work three days or two days or one day or six days or seven days to feel supported and be successful? What if....take a deep breath...the employee only needs to work one or two hours a day or more or less to feel supported and be successful?
Why are these "solutions" offered? Most would suggest, in response to employees wanting, needing, and asking for something different. But what is it, specifically, that employees want, need, and are asking for?
Flexibility focuses on time. Hybrid focuses on location. Four-day workweek focuses on time. And each of them is designed, monitored, and doled out with all kinds of rules by someone else.
What employees on all levels are REALLY asking for is more control over how they spend their time (without judgment) and for their performance to be objectively managed/measured.
Of course, when employees who have been denied such control over their lives for so long are "granted" or "permitted" a change, it does feel meaningful and shapeshifting.
But...
Just imagine what it would feel like to not need a program, a policy, or permission to live your life and get your work done in your own way, every moment of every day. (and the best part is, the pathway to realizing that kind of life already exists)