Isn't the point more one of de-anglicisation rather than an attempt at re-gaelicisation which may or may not have worked?

The Western Isles Councils decided some years ago that all anglicised names would be removed from road signs and town names so eg you will not see any references to Stornoway just Steornabhagh. (Brown tourist signs are the exception which understandably give anglicised translations where necessary but they are erected by the tourist boards.)

Callanish (the village) would be included process and I assume the residents agreed to the chosen Calanais.

The actual entymology here is more a matter of academic interest.