Depending on how extreme you want to take the concept of "free market," offer incentives to groups of people to celebrate meaningful cultural holidays on different days. Pay the Greek Orthodox to switch back to the Julian calendar for Christmas (so they'd celebrate on January 7 on the Gregorian calendar), market Kwanzaa like crazy, rebrand the feast of St. Nicholas (December 6) as Santa Claus Day and make a cultural norm of gift-giving then instead of on Christmas, etc.

Honestly, even though I care a lot about attending church services for Christmas, I have never really cared about visiting family and friends on Christmas specifically - it's just logistically complicated and expensive and falls at a stressful time of the year. If you gave me a way to go fly to visit my family on some cheaper day and have it count for the same cultural expectation, I would very enthusiastically take it.