Argthtjtr

I think you're giving the elves short shrift here. In particular, I think you may be focusing on the wrong elves.

Consider the svartálfar or "black elves" in Norse mythology, who were responsible for crafting a golden wig for Sif among other treasures - and are often conflated with the dwarfs, who have even more amazing feats discussed in this Literature.SE answer. Creatures capable of forging a self-duplicating gold ring, a boar with golden fur, a ship that can be folded up and put in one's pocket, and many unique weapons (including Mjölnir and Gungnir) clearly know secrets we've yet to plumb about the mysteries of the universe. I'm not going to bet that they can't handcraft modern electronics.

The most obvious course is to use a variation on the folding-ship technique: work on the circuits at an expanded size that's more amenable to handcrafting (keeping in mind their ability to work individual strands of golden hair), then shrink them down to their "proper" size. Or if that's not dramatic enough, maybe it's the workers who are folded down to tinker with individual circuits.

Sure, it's slow, but you can't put a price on proper (mythic) craftsmanship.

There are several foundries all around the world, producing integrated circuits for all our needs. These foundries run 24/7.

Once in a while some produced chip is defective, and get discarded from the production line.

Well, the trick is, the chip is not really defective. It's just a toll to Santa's production line. Then, once the chip is available, the elves can use their skills to assembly it into the desired product.

Santa not only have power to give things to kids who celebrate Christmas, but also the power to take things from ones who don't. Like those children who work at assembly lines in China or India.
Elves? Just a cover-up story.

The workers in chinese factories who assemble iPhones aren't very skilled either. Chips are printed by machines.

Elves are just the cheapest manual labor available, and Santa has just one upped every other third world country by having his assembly factory where no labor laws can reach.

Much to the surprise of conspiracy theorists everywhere, the true role of the Illuminati is that of Santa's supply chain. When the department of defense budgets $600.00 for a hammer, it is really buying components for Santa's elf minions.

Santa-type elves, Elfus SaintNickalus Arcticus, operate Santa's electronics manufacturing equipment building the printed circuit boards and microchips. Additional elves assemble these electronic components. Elves are excellent electronics manufacturers because of their small hands and mentorship training from other elves. They are excellent solderers and many are NASA certified. In fact, many elves worked on classified NASA projects because they were able to crawl inside the avionics compartments of the early space rockets which no human technicians were able to do. After the Cold War, the elves returned to Santa's toy production facility at the North Pole under the auspices of the United States Air Force during Operation Binderclip. This was all scrubbed from the official record to keep Santa's Workshop from becoming a primary nuclear target for anti-Christmas Soviet war planners. That's why I couldn't link any non-classified sources for you.

Think about it: why does NORAD track Santa every Christmas season? It's how NASA and the USAF honor him for his still-secret contributions to space science.

easy: Automated / computerized pick-and-place technology with board manufacturing on CnC routing, drilling, and soldering tables that have been computerized and fit into the assembly line. The elves run the robotic processes and troubleshoot issues on the assembly / production line, and refill the bins of components as they come in from IRT ordering vendors.

Did you ever see Santa distributing complex electronic toys without wearing the brand of a maker ? The trick is there : Santa's elves only build unbranded toys. For trademark reasons, all branded toys are bought from their respective makers.

Santa has always been incredibly wealthy. The easiest and simplest thing for Santa to do is to sell toys to the open market and invest the profits in the stock market. If Santa had started doing this in 1933 during the great depression, he is easily the richest individual in the world, and can easily afford all the electronics that he desires. Giving away toys once a year would be one of the best marketing tactics to increase toy sales during the other 364 days of the year. Santa can easily afford to own significant portions of large toy and electronic retailers and manufacturers around the globe, as well as significant real estate for the polar express. It's no secret that his marketing works incredibly well - Boxing Day is one of the biggest sales days of the year.

There is no requirement whatsoever that in our increasingly global economy, that Santa's elves should have to assemble every part of every toy by hand. No matter how many integrated circuits are involved in toys, there is always going to be a degree of manual labour and final assembly or testing that is required to ensure the quality, as well as selecting toys which children will enjoy. While some skill shifting is inevitable, with the increasing population and wide variety of desired toys from the good boys and girls all across the globe, I have no doubt that Santa can easily keep a full-time staff of elves as he always has.

So there you have it, Santa is incredibly wealthy, orders and ships parts to the north pole using the polar express, and does the final assembly and testing using the same crew of elves he always has.