The usual explanation goes by saying that Japanese express their admiration by copying. However, I find this explanation hard to swallow.
Some Pilot models. From left to right, Custom Sterling (1976), Custom 743 (2009), Super 100 (late 1950s or early 1960s), Custom 742 (2009), Super 200 (1960).
The Montblanc Meisterstück was created in the late 1940s and early 1950s. During the 1960s and 1970s, Japanese companies did not copy them. Pilot’s Custom models or equivalent (the Super series) could be equally boring in looks, but they were also different.
Actually, only in the 1980s modern torpedo pens were marketed. It was on 1983 when Pilot created the limited edition Pilot 65 on the occasion of their 65th anniversary. With some minor variations, that model is nowadays the Custom 74.
My conclusion is that this copying strategy obeys to marketing arguments: Give ’em what they want! And the general public still thinks of Montblanc when fountain pens are in the conversation.
From top to bottom, Sailor's Junior 21 K gold nib, Montblanc's 14 K gold nib in a 144, Platinum's music nib, Pilot's falcon nib in size 15. All of them in boring-looking torpedo style pens.
Luckily enough, Japanese nibs are a lot more exciting than their boring Montblanc counterparts of these days.