Why are so many east bay cities named after east coast cities?

They were named later and the US is a big country. Many names were recycled. Many came from the British Isles to begin with.

We are not aware those are eastern cities. How do you know which came first? It is probably a coincidence. We have plenty of Spanish names in California. You forget how large California is, so we probably ran out of Spanish names and had to revert to colonial British names.

Did you do any research?

Albany is named after the birthplace of the city's first mayor which was Albany, NY. There are 28 states with cities using that name.

Richmond is named after the birthplace of a state assemblyman who got it named that. There are 23 states with cities using that name.

Newark is named after Newark Castle in Scotland. Three are 15 states with cities using that name.

Concord..no idea why it was named that. There are 10 states with cities using that name.

Pittsburg was named after Pitssburgh, PA because of the first industry (steel) which existed there. (At the time, the PA city commonly didn't use the H.) There 30+ cities in the US with that name.

Are you sure they're named after the east coast cities? They might be named after those cities or they might be named after what those cities were named after. Concord is named for an historical event; maybe the 20-plus other Concords in the US are named that for the same reason. People tend to name new places after the old places they came from, for nostalgic reasons.

Probably half or more of the places in North America are named for places in the UK and Europe.