My verdict? The Rankin-Bass version of Santa Claus' autobiography, the stop-motion television special Santa Claus is Coming to Town (1970), remains the superior version of Santa's origin, based on those that I'm familiar with.
The real deal.
The 1985 movie starts out with him Mr. Claus as a benevolent, big-hearted, jovial, er, rounded, beared a in what seems to be medieval northern Europe who just loves to bring toys to kids on Christmas eve. So far, great. Fitting tone-wise and in consideration of the myth's historical roots. But then, he gets caught in a blizzard ... and is rescued by a gaggle of elves (who look and sound like New Yorkers and are dressed in what seem to be costumes for a children's play), who have, as they state, been "waiting for" him, so as to "fulfill the prophecy". And so, suddenly, unexpectedly bestowed upon him are his North Pole home, and adjacent toy factory, sleigh, flying reindeer (who, you know, in wide are live animals but who, jarringly, are weird-proportioned, lazy-eyed puppets), and a plan to fly all across the world on Christmas Eve delivering presents to children. Everything's squarely in place, ready and waiting for him, ready to go. Makes him seem like a doddering old man who stumbled his way into the elusive entity that is blind luck. It's lazy writing, glossing over all the why's and how's. "We're gonna tell you the story of how Santa Claus became Santa Claus ... mehhhhhh, we don't wanna bother to figure out how all that stuff came to be, so it was just already there, okay?"
But at least once the movie gets past its initial "Here, Santa, this is your new home! Here Santa, this is your toy factory! Here, Santa, these are your reindeer!" stage and an actual story (about a rogue elf, a crooked toy industry monopolist who wants to run Santa out of business, a homeless little boy, and the crooked toy industry monopolist's kind-hearted child niece, who befriends the homeless little boy) gets underway, it's not bad.
And at least one aspect of the movie has brought out the kid in me: despite the obvious green screening/blue screening/whatever it is, to behold Santa guiding his reindeer-driven flying sleigh approach, soar over, zip around, and land on the rooftops of Manhattan is to be mesmerized, thrilled at a base level. After all, I still wish that's what really happened each Christmas.