It's not apples to apples, you're never going to find a good comparison. Hot Toys doesn't have the infrastructure that Sideshow does. Hot Toys doesn't have a CS staff to answer your questions and respond to replacement inquiries, nor shipping and warehouse staff.
And while I believe that Threezero does have CS staff, it is likely tiny compared to Sideshow. They simply don't have the size. And their sculpts are hit and miss, just like Sideshow, so I don't see the argument there.
On top of that Threezero and Hot Toys aren't paying for overseas shipping when they manufacture product. When Sideshow product is produced they have to pay for container shipping to get it from China to the US warehouse, then ship out their individual orders.
You'll notice that the other "foreign' manufacturers, (non-Eastern, I don't know the best term) but companies like Sideshow, Mondo, Big Chief (RIP), Kaustic Plastik, all of their prices are comparatively higher than your similarly-scaled licensed counterparts. Which I believe is due the the fact that they're not located close to the factories and have to send representatives to monitor the factory progress, and aren't able to keep an eye on production in a cost-effective manner. Threezero and Hot Toys are located close to the factories so it is less expensive for them to station a representative to monitor production.
Further, you seem to not have a problem with Kaustic's $300 price tag for Chuck Norris and say it seems "appropriate", but seem upset by a $300 for Sideshow Clint Eastwood. I'm reasonably certain that Clint Eastwood wants a higher license fee than Chuck Norris, so again, I'm not terribly surprised that Clint Eastwood figures are more expensive.
And one other thing to keep in mind, I assume that the Clint Eastwood license is an additional cost on top of the movie license, e.g. Sideshow has to pay the movie studio to call the figure Blondie and put The Good, The Bad, and The Ugly on the box, and they have to pay Clint Eastwood as well. For Hot Toys, they are only paying Disney the license fee, they aren't paying the actor a fee as well. The Star Wars license includes "all" actor likenesses as well. There seems to be some debate that the Star Wars license no longer includes Harrison Ford, I find that fact debatable, but it's not relevant to this discussion.
Having said that, I'm reasonably certain that the total license fees for GBU and Clint Eastwood likeness put together is much higher than the total license fees for Missing in Action and the Chuck Norris likeness, if the likeness is not already included in the movie license rights, but considering the age of the movie, it likely does not include likeness rights.
And to reply to your recent post about Redman, saying that figure looks better. It's because it's a recast of a custom sculpt by iminime, it's not their work, it's just something they essentially stole from someone else. It's cheap because they didn't pay to develop the figure, and it looks good because they basically Xeroxed a figure that looked good to start off with.
For an example, I have a set of the Olly Moss Star Wars posters, there's a set on eBay now for $17k, which is an insane amount of money. I paid $150 for the set when they went on sale. But there are a ton of knock-off prints and scans. To me, it's really ****** that people are selling scanned versions of this artwork. Not that it devalues my set, but I just think it's ****** that people are profiting off work that they didn't create.
But in your case, it's like questioning why the posters cost $150, when I can just buy the posters on Estsy for $40.