No. They're doing it because it's marginally cheaper and more convenient in the aggregate, but if they didn't and stuck to cane sugar, the practical difference on the consumer side in terms of consumption and price per product would be essentially nil or close enough not to matter.

It's not about displacing other sugars. It's a cheap substitute for things not sugar. The argument about corn syrup is misplaced, it should be about sugars in general in US processed food. But corn syrup just happened to be that sugar.

No, ostensibly it's cheaper at scale. But from a consumer's perspective, it doesn't matter that they're using that instead of sugar. There's a much larger conversation to be had about the misinformation surrounding sugar and carbohydrates, but anyways..