It seems that the Alpnisit with green dial will back in production early 2020 with a new movement. [1]
[1] https://www.seiyajapan.com/blogs/news/the-alpinist-will-make...
[1] https://www.seiyajapan.com/blogs/news/the-alpinist-will-make...
After 4S15 was discontinued, Alpinists based on 6R15 have been produced for many years, but they are nowhere as sought after as the 4S15 version.
...but for a much higher price.
I really don't appreciate how Seiko is upselling certain segments of their products. I feel the customers are being milked without getting the once excellent value in return anymore.