I'm personally observing that soda companies have diversified their products across sugary drinks and foods, acquisition or new proxy companies even (at least here in Asia). So called sports drinks, fruit juices, coffee/milk/chocolate/soy based sugary drinks, even oat-meals/cereals have over the years increased in SKUs; I bet the net sugar consumption would still be higher if you account all of these.

It's just not the soda. The hidden sugar i.e. high fructose corn syrup is not literally in almost every imaginable product.

Do you have a source for this? The data I've seen in peer reviewed publications are based primarily on NHANES data, which doesn't cover recent history.

I've seen a Beverage Marketing Corporation graph that shows a 1% decline in soft drinks, but a 4-5% increase in ready-to-drink tea, sports drinks, and energy drinks. The raw Excel data is sold for $3000, so I don't know what the absolute values are, but it seems likely the decline is soda is largely being offset by equivalently bad/sugary replacement drinks.