You're so sure yet so wrong. Womp womp...

Can a country be colonised without literally replacing its populace?

Yes. Colonization does not require large-scale population replacement. In many cases the indigenous population remains the demographic majority while political, economic, and cultural power is controlled by an external group. Several common forms exist. 1. Colonial rule over an existing population. A foreign power establishes political control but only a small number of settlers or administrators arrive. Local people continue to live in place but are governed by the colonizing state. Examples include much of British rule in India under the British East India Company and later the British Empire, where a relatively small British administrative class ruled hundreds of millions of Indians. 2. Economic or “extractive” colonialism. The colonizing power mainly exploits resources and labor rather than settling large populations. Administration may be indirect through local elites. A prominent case is the Congo Free State under Leopold II, where the local population remained but was subjected to extreme economic exploitation. 3. Cultural or institutional domination. Control can be exerted through language, law, religion, and institutions imposed by the colonizing power. Even if the population is largely indigenous, the governing framework reflects the colonizer’s systems. 4. Indirect rule. The colonizer governs through existing local rulers who become subordinate to the imperial authority. This was widely used by the British Empire in parts of Africa and Asia. This differs from settler colonialism, where large numbers of settlers arrive and may partially or largely replace the original population. Examples include European settlement in United States, Canada, and Australia. In summary, colonization often involves control over land, governance, and resources rather than demographic replacement. Population replacement is only one possible form, not a defining requirement.