Why do the Warriors need a new stadium?

From the San Francisco Waterfront Alliance

I'm a Warriors fan. During the broadcast of last night's game, it was announced that the Golden State Warriors have sold out 58 straight games at the Oracle Arena, the largest NBA stadium in the state:

When the arena reopened in time for the 1997-98 season, its new capacity was 19,596, making it the largest of the four NBA arenas in California by capacity. It remains such as of 2014, with Staples Center (the current home of both the Lakers and Clippers) second and the Sleep Train Arena in Sacramento third.

It was easy for the 49ers to make a case for a new stadium, since Candlestick Park was/is the oldest stadium in the NFL, except for Lambeau Field in Green Bay and Soldier Field in Chicago.

But Oracle Arena is easily accessible from the whole Bay Area and has a nice big parking lot with 10,000 spaces. So what's the problem?

The Warriors' stadium project will be discussed at this meeting on February 3.