In California specifically there are also environmental regulations like CEQA that provide another avenue for blocking such things, independent of eminent domain issues. Even if someone is building on their own land, lots of environmental review is required, and individuals or groups can sue on the basis that such review was inadequate. This ties things up for a long time. There are legitimate reasons to want environmental review, but the way it works in CA now, CEQA is largely just a tool people use to delay projects they don't want.

Most countries has that but it still doesn't take many decades to build a simple piece of railway.