The argument for a remake falls down when people say the original film is "dated" and that a new audience doesn't want to see such a dated film.
The source material is dated so what do you do?
Ignore the time in which it was written and set?
I agree with people saying the earlier Pygmalion film was better (Wendy Hillier) and that could be remade as a period piece and audiences will understand that they are watching a historical/period piece.
But how do you translate a musical for a modern audience if that same audience can't watch a version that was made when the times depicted were in living memory?
There is a mass of social commentry, the whole film is social commentry. But of the times it was written.
How will a modern audience who people say don't want to watch a "dated" film, relate to a modern version that still includes the whole idea of only being able to work in a shop if your accent is correct?
And that once the accent and manners are learnt "what am I fit for".
And then they sing a song about it.
In 21C Britain?
It's the fact that it is a musical is where it will fall down. The audience that can accept it being a period piece wouldn't/won't have a problem with the original anyway.
So what audience will the film be aiming for?