[TZubiri]

Probably related that it pertains to a game built on a 2000 engine. The lack of complexity and repetitiveness is built into the game, which directly correlates to the popularity among the autism community.

[spondylosaurus]

OSRS is forked from a build of RuneScape from 2007, actually :)

[TZubiri]

And the tick based SQL + Java engine was built in 2004 when it migrated from RS classic to RS2.