I was able to understand to Switch and PS4 shortages before since consoles have many components  but how hard can it be to produce cartridges and print the cover art for a game?

It is a whole progress, they have an air tight shedule with no much room to wiggle, so when shortages happen they need to find Time/Room/workers/Extra delivers so all they can manage is a low amount 10/20k to minimize the extra costs.    During the Nes Era if you wanted an extra 10K of a game Nintendo said no, the extra cost made it not worth to print.

It isn't easy to just make the cartridges and get them shipped. However a lot of this seems to be Square Enix being conservative in how many they make and ship to their Japanese retail partners. 

It may have to do with the Switch ' s game cards being more intensive or costly to have to make compared to discs or them being burned on the nostalgia market after failed attempts with Lost Sphear and the Secret of Mana remake this year. In either case much like Nier Automata they stumbled on a sleeper.

Amazing game and deserves to sell. I am loving it.

And yet it won't amount to anything. S-E and many other Devs see Nintendo platforms as the place to release niche or B-games. They will not even consider a mainline FF game, or KH3. Maybe the system cannot run these games, but this is also S-Es choice and made willingly so: they prioritize graphical fidelity at the expense of gameplay for a very long time now.

If a game does well, that is good. If a game does not do well, well we told you so games don't sell on Nintendo platforms.

If S-E wanted to be even a tiny bit more adventurous, they would at least have a Crystal Chronicles on the pipeline. Nope, not even that. Watch them re-release a couple of low key ports and call it a day.

Pretty sure gamers want CC less than SE wants to make one.lol

Cost isn't likely worth it? Game is selling out, but it's not like they're printing hundreds of thousands of copies each week. If anything, preorders will be better for Octopath 2 so retailers will order more.

Not to pick on you specifically since it is not an uncommon complaint, but man do I find this kind of cynicism tiring.  The Switch simply will not be the home of AAA titles due to the conscious decisions of Nintendo itself.  There's no reason to get mad at Square Enix for keeping its AAAs on PS4, especially when they continue to put solid AA's like Bravely and Octopath on Nintendo's consoles.  

Also, I would suggest that Octopath Traveler is quite a bit more adventurous than slapping the Final Fantasy name on some generic game (which is basically what the Crystal Chronicles sub-series was).   And, SE has actually been a prolific publisher for Switch already.  They've got 17 games released or announced already, many from within their own development studios, and have created a team dedicated to Switch.  They clearly aren't just into "a couple of low key ports and call it a day" mode.