In "The Rocking-Horse Winner," how do you explain the ever louder voices in the house?

It is important to realise that D. H. Lawrence used this
story as a vehicle for expressing his own concerns and worries about materialism and
greed and how it could destroy individuals and families. Interestingly, the mother in
this story was actually based on one of the author's friends, and apparently displayed
very similar characteristics. It is clear that the voices in the story become louder and
louder at a key moment when Paul has organised for his mother to receive some of the
money that he has won through his gambling. What is interesting is that, instead of
becoming quieter, the voices actually do the
opposite:

And
yet, the voices in the house, behind the sprays of mimosa and almond blossom, and from
under the piles of iridescent cushions, simply trilled and screamed in a sort of
ecstasy: "There must be more money! Oh; there must be more money. Oh, now, now!
Now--there must be more money!--more than ever! More than
ever!"

Thus Lawrence shows
the self-destructive cycle that greed and materialism can lead us into, and how, when we
have gained some money, it appears to be never enough, and only drives us on to seek
more and more and more.