this is a theme in the play because Mr Birling is a strong microcosm of Capitalistic views that society had at the time the play was written
Inspector Goole could be said to be a mouthpiece of the writers views as he is a strong microcosm for Socialistic views which the writer wanted for the world back when it was written
Capitalism
a system of government that runs based on selfishness and ignorance towards other people because as long as they are happy and have enough money then everyone else in their eyes doesnt matter
socialism
a system of which leads with the power of people instead of the power that money gives as they think that peoples wellbeing is more important