High fructose:glucose ratios definitely exist in nature.

Agave syrup is 4:1. Apples and pears are around 2:1.

Moreover, high fructose corn syrup is a bit of a misnomer. Most HFCS used in food are 42% fructose, 58% glucose. The ones used in soda are typically 55:45.

That makes even the latter's ratio lower than say, watermelon, papaya, pears, apples, mango, blackberries, etc.