I'd like to think that "railfan" was the explanation but I think it has a lot more to do with shaving costs - even though I cannot see that recording the announcements can be a large expense.
Railsounds crew and tower talk have gone through a few transformations; I think that RS5 from about 2005 was the best with engine-specific announcements and even some regional accents. Today under Legacy you only get something like that with Vision Line engines and a year or so ago there were several threads here about Lionel's decision to offer only "generic" crew and tower sounds on non-Vision engines.
