I've never heard anyone suggest that Britain should have focused on improving conditions at home before engaging in empire building. I always assumed the two were not mutually dependent. The expenses in running an empire probably paid for itself and no doubt returned a lot on the initial investment (after all the whole point of having an empire is to secure better trading). Meanwhile the conditions in the cities were a separate problem, and one which was hard to fix quickly given the population explosion and the Industrial Revolution.

All of which to say, is while you raise an excellent point all the evidence i've seen suggests the two are entirely unrelated projects. If anything increasing globalisation in the long term increased prosperity for everyone involved (just not necessarily by equal amounts) and vastly improved conditions.

If anyone has a counterpoint, by which i mean historical complaints or serious academic analysis, i'm happy to hear. None of this is a moral judgement on the relative evils and merits of empires and Victorian England, which is not the topic, just my opinion of why from a practical standpoint one has very little to do with the other.

It’s not at all clear the costs of running the empire were outweighed by the benefits: https://iea.org.uk/media/empire-and-slavery-did-not-make-bri...

“The book highlights that most of Britain’s economic growth in the imperial period did not come from its colonies. Trade only accounted for about a quarter of economic output, and most of that trade was with Western Europe and North America — not the Empire. For that reason alone, the Empire cannot have been the decisive factor explaining domestic investment and later wealth.”