Interestingly, this is related to a question of whether being religious is a good thing because of the various associated benefits, even if it brings certain grave flaws, and an objection that certainly religion with all its lies can't be anywhere near the best thing to practice, that one can greatly improve on the status quo. But guess what, it's hard to improve on the status quo, it may be a right thing for the humanity to try, but it may be an impossible thing for a person to try. So, you need to choose not between the status quo and the best thing that's theoretically possible to construct, but between the status quo and the best thing that you, personally, can construct.

So, the Santa Claus lie has a benefit of pervasiveness in the culture, everyone repeats it. You can't fake this for a different, improved lie.