To be honest the fact that this topic even arises, to me, is a sign that there's a lot of adults who've no clue about the difference between adults and children and want to treat children as little adults to be treated to cool, callous disillusionment, which is not even the reality of all adults but the reality of a certain population of adults who lose heart and hope in the second phase of life.
I've encountered it in person, in reality too with couples, particularly estranged couples, fighting about whether or not schooling children in non-belief is robbing them of a certain innocence.
*skipping the last 3 pages because its probably just people saying "I'm right so therefore your stupid!"* .........to the OP.....I wish I still believed in Santa. I think we all could use a little magic sometimes!
Taught Santa, tooth fairy and Easter Bunny.
My parents (mother, mainly; my father only went along with it) were smart enough to adapt the Santa story to a city apartment building by saying Santa came down the fire escape, since there was no fire place.
As I grew up, we (my father mostly) watched nature shows on PBS, and of course, you learned some science in school as well.
There were no flying reindeer even mentioned; as well as magical bunnies or fairies. There was also no God, Satan, angels or Jesus Christ ever mentioned either (my parents were agnostic, but their parents' generation taught me that stuff); but instead, a cosmology that differed vastly from the Bible (though I did not know much detail on that, and wasn't aware of the conflict. So at one point, I assumed there was this ape somewhere, who one day gave birth to Adam and Eve).
So I then began questioning all of that stuff. Santa and the other stories were more like obvious fiction you read or watch on TV.
Plus, it was not really consistent. The Santa whose lap you sat on in the store was assumed to be the real one. Yet, the times being as they were in the 70's, when I got to choose between a white or black Santa (plus the fact that there was more than one in the first place), called that into question.
The quick response: "those are just his helpers".
But the final realization was that the toys I got were the regular brand of stuff you see in the store; manufactured by the well known toy companies who advertize all year long, rather than specially made at Santa's North Pole factory. (After all, they are what you see and then pick out of the store, so they're already made, and only need to be bought. And then on rare occasions, you do get them at other times of the year).
IIRC, there may have been an attempt to patch that up with the "Santa's helpers" line, but this was pushing things further and further from the story, by now.
From there, the whole mythos just dissolved, especially once I rethought the whole fire escape thing. Why wouldn't this ever be mentioned in the stories? Yes, they reflect a suburban mindset, but those producers must be aware of other types of housing.
So since it had to be a chimney, I realized that there was a big chimney in the building for the boiler, and it was right on the other side of the wall from our bathtub. Still, he would then have to pass through walls. Further and further from scientific reality.
My very last image was of Santa with regular reindeer pulling a sleigh down Flatbush Ave. from the toy store to our house, and probably using the door like everyone else.
(Let's not forget the question of how this could be done for every child in the world in a single night).
At that point, it just figured that it must be just my parents.
I then go to them yelling "You lied to me!" (my mother still recollects this). I couldn't believe they would teach me something not true, so seriously.
(Of course, the final thing to go would be religion, and for some reason, they never sat me down and explained their beliefs (other than ranting about religion at times, and how it was often used for racism and mind control). So I pretty much arrived at my own conclusion. In adulthood, several things turned me back around, but it's been very hard to hold on to faith).
So it provided years of exciting memories (plus a handy tool to motivate us to be good), but we don't believe in teaching it. It is basically an artificial "God"/"Jesus" who has some of the same attributes, such as omniscience, virtual omnipresence, supernatural powers, and a sort of judge of good and bad. Hence, when one falls, it's likely the other might go with it.