Nah, the San Jose local accent is distinctive and it's not on any national news.

The newscaster accent from the '80s was a real thing but it was upper-midwest. Tom Brokaw is the canonical example.

Yeah that's a midlands accent. It sounds hard to place, but you can tell where it isn't. It's not a Philadelphian, or a new Yorker, or anywhere on the east coast really (so many accents over there). Definitely not Californian or southern. So really it just sounds like the midwest (not Minnesota) or like it might be Pacific Northwest. The big thing though is it's easy to understand. Boston or Baltimore for example would be terrible accents to make the default for newscasters.

Really it's like how the BBC has an accent

Go tell that to any linguist and get laughed at.