Entrance Roundels with the station name

[74A]

I always thought it would be helpful if the London Underground roundels at the entrance had the name of the station rather than Underground.

I was watching a video on youtube about Lambeth North and in one old photo the entrance roundel does have the name in it.

So did all entrance roundel use to display the station name ? And if they did why did they change it ?

 

[Dstock7080]

The station identifier is Underground.
Acton Town has a named roundel

 

[edwin_m]

If you are outside the station you probably already know where you are, and if you're interested in the station it's because you want to be somewhere else. So a roundel on the outside of the station is primarily advertising access to the transport network and the name of the station is secondary. Conversely, arriving on a train you already know you are on the Underground (overground, whatever) so the station name is emphasised so people know whether this is where they need to alight.