It was very hard to sell the idea of colonization to places as diverse as Australia, Canada, and South Africa without including in it the promise of something better than dirty, crowded, oppressive, 19th century Britain. The other part of the question is: how much effort do you, as the British Government, want to spend overseeing and controlling some bastard shepherd in New South Wales or some bastard lumberjack in British Columbia (hacking down the mighty larch, no doubt) or some bastard diamond miner in the Rand territory when WHAT YOU WANT is the STUFF they produce and to TAX it? Let them have any kind of damn government they want so long as the money heads to LONDON.