Population pressure has never been a historic justification for colonization. Colonies have been used as relief valves, but the pressures were more social or political in nature (transporting prisoners to New South Wales, frex, or the Nonconformist settlements in the Americas).
The missing justification for colonies is the classic "make a shitload of money." Pretty much all the major colony efforts in the Americas, as well as the colonization of India, China and the scramble for Africa, were justified by the promise of gold, silver, spices or some other valuable commodity just sitting out there waiting for somebody to dig them up. Most of these didn't pan out exactly as planned of course, but that was the plan...
Mr. Fnord interdimensional man of mystery
FenWiki - Your One-Stop Shop for Fenspace Information
"I. Drink. Your. NERDRAGE!"
The missing justification for colonies is the classic "make a shitload of money." Pretty much all the major colony efforts in the Americas, as well as the colonization of India, China and the scramble for Africa, were justified by the promise of gold, silver, spices or some other valuable commodity just sitting out there waiting for somebody to dig them up. Most of these didn't pan out exactly as planned of course, but that was the plan...
Mr. Fnord interdimensional man of mystery
FenWiki - Your One-Stop Shop for Fenspace Information
"I. Drink. Your. NERDRAGE!"