Final answer:
British merchants and landowners agreed to send more soldiers to maintain economic stability and political dominance, ensure the protection of trade and frontier territories, and raise revenue to pay off wartime debts, which all aligned with their interests.
Step-by-step explanation:
The question as to why British merchants and landowners supported sending more soldiers relates to the economic and political context of the time. The massive debt from wars necessitated increased security on the frontier to avoid further costly conflicts. The British Parliament needed to enforce imperial trade laws more strictly and find ways to raise revenue to pay off the war debts, expecting contributions from all British subjects, including those in the American colonies.
Also, the spread of the British Empire, particularly following victories like the Seven Years' War, required a strong military presence to maintain economic dominance and protect colonies and trade routes, as evidenced by the deployment of troops to Boston in 1768 to quell unrest.
To maintain imperial power and the economic benefits it generated, sending more soldiers was deemed necessary. Merchants and landowners, who benefited from empire expansion and secure trade, would agree to sending more soldiers to maintain the status quo that favored them.
This need for military presence was further underlined by the potential unrest or resistance from local populations, including Indian tribes who also preferred British rule, fearing American expansion might lead to greater loss of their lands.