One of the biggest sources of the world's sugar today is corn (as High Fructose Corn Syrup), which is a rather expensive "concentration" process but is heavily subsidized in the United States by a large number of interlocking subsidies in US's strange, complex multi-grade corn system which leads to "cheap" access of lots of "waste" corn that that is "cheap as free" enough that the expensive "concentration" efforts are still profitable at cheap costs.
One of the "best" sources of "plain" white sucrose (versus fruit's heavier balance of fructose) is sugar cane, which is a plant that prefers sub-tropical regions and often islands at that and historically required massive plantations with slave labor to get cheap and today involve massive expensive industrial harvesters and international cooperation of subsidies, grants, and colonial legacies.
Maple trees grow in northern climates and real Maple syrups are expensive today as a number of subsidies expired and demand outpaced production and even available supply.
Other fruit syrups compete against the primary uses of their fruits.
I started from USA agriculture because it dominates import/exports, but I did a winding expansion to North American and Pacific Island and Caribbean sources and then finally much of the remainder of the world's sources (though I said "fruit" and definitely forgot about beets, which few would classify as a fruit, that is something I missed). It's a global market and you can't talk about how cheap refined sugar is without starting from the cheapest/highest-volume sources of it. (Just like you can't talk about European oil prices without starting at OPEC/Middle East and then the US Gulf Coast even if you eventually wanted to just talk about Scottish off-shore oil prices. The other forces are bigger so they have an impact on the market prices.)
