the US is a massive nation both population-wise and geographically so you really cant compare to other nations. Anyway even in Canada I believe the General Election takes nearly 2 months in a nation almost 10 times less populated than ours so our general election season really isn't that long.
As for the whole process , well that is cause we choose our nominees and have the general election in the same cycle while in Canada and Europe thats a separate process that are years apart.
India has a population of 1 billion people, and while it has a lengthy election process compared to most countries it is nowhere near the year and a half long us elections.
