Why did the collection of income tax after World War One continue?
There is a lot of political back story on this one. In short, the Conservatives were in power pretty much exclusively between Confederation and the end of WWI. They introduced the National Policy. It imposed duties on imported goods, which was intended to increase the manufacturing sector and increase immigration (the lack of income tax being an enticement). The government’s primary source of revenue was from the duties paid on imported goods. If you manufactured farm equipment, you supported the National Policy. If you were a farmer, you were opposed to it – farmers would end up paying more for farm equipment, but couldn’t get more income from their produce. The Liberals during this era were in support of free trade with the US instead of imposing duties. This of course would mean they would need to implement a different tax to replace the duties. The conservatives reluctantly imposed the temporary income tax during WWI in order to fund the war effort. It remained in place immediately
