It also has really peaky demand. Downtown San Jose doesn't have a lot going on most weekends. Also the Orange Line serves both Levi's Stadium and a lot of stations closer to industrial and/or business office sites. You get a lot of weekday peak rush traffic but not much else unless something's going on at the stadium.
It's almost like "commuter light rail" outside of the immediate downtown-to-Airport section. It doesn't help when offices closed during the pandemic and/or decide to reduce office space after the pandemic (or fold entirely).