Respectfully, your argument is missing the boat in a couple of key aspects:
1) The Sumo is a Japan market only watch. It is a mid-market diver timepiece with excellent fit/finish and a well regarded in-house mechanical caliber, the 6r15, which hacks, hand winds, has a 50 hour power reserve and pretty respectable, COSC like accuracy right out of the box. From that perspective, less than USD $500 for a watch of that caliber strikes me as a bargain. Please show me a Seiko mechanical diver (Or any Seiko mechanical watch of similar quality) from the official US Seiko catalog that even begins to approach the finish and quality of the Sumo.... You'll find none I am afraid.
Keep in mind also, that the 6r15 movement is not currently offered on ANY export Seiko mechanical watches at present. If you want a 6r15 Seiko, you have no choice but to order it from Japan.
2) Watches in Japan are more expensive than anywhere else in the world. But their finish and quality is also a notch or two above export versions of similar models. Also the Dollar vs Yen exchange rates situation doesn't help us either but the Dollar has gained a little ground against the JPY in the last month or so.
Also Seiko is going upmarket and some of their newer pieces exhibit a higher degree of finish quality.
Unfortunately, the vast majority of Americans when they think of Seiko, they think of Kinetic and quartz "mediocre" mall offerings and have no idea or exposure to their finest pieces from the Japan domestic market or their luxury lines like Grand Seiko.
I am sure you would cringe at the price tags of the recently released Seiko Anantas. The cheapest Ananta automatic starts at $2,000 all the way up to $6,400 for the Spring Drive Chronograph.
The sad reality is that fine Seiko mechanical watches like the Spirit and SARB series would not sell well in the USA. The vast majority of people doesn't know anything about watches, lack appreciation for well made mechanical movements and would bark at the thought of paying $500 for a Seiko SARB dress mechanical watch. If a SARB or Sumo diver had the "Swiss made" at the bottom of the dial, rest assured that those watches would easily be double or triple their suggested retail values.
Prior I used to think that Seiko's upmarket drive was misguided. But after buying a couple of Japan market Seiko SARB mechanical watches and 2 new Anantas, my perception on their strategy has changed 360 degrees.