Probably because the best unit (for Roosevelt) is draw only, with tags very limited (also, these are "Cascade Roosevelt" west of Pac.Crest trail, and east of I-5). or other special permits that give timing of the rut, or other "advantages" to permit holders in combination with a general tag, in areas adjacent to the Olympic National Park.
The WDFW manages game numbers by offering general season hunts with lower chance of success, and special permits for longer seasons or better dates, restricted areas etc..
permits average an 80% success rate, while "general" season is closer to 10%...

But this is a statewide deal, not just Roosevelt.