Why is the rivers in central nevada not part of a major river system?

Most of it's rivers are laminar, tiny, small and do not have any major outlets into any collecting sea

Explanation:

Central Navada has an unusual special topography, varying climate, and arguably contrasting water sources, capacity, outlets and tributaries. None of it's rivers apart from Colorado River has a capacity to feed into a sea. Infact, because of how arid and dried this area is, most of it's reservoirs are completely utilized for irrigation farming and other utility functions.

Some of it's other rivers are:

Meadow valley wash, Reese river, brunear river, Carson river, Humboldt, duck Creek, Mary's river, muddy river, quinn river etc.