Exactly this. Even if your demographic is the same as the chart, dropping 2% of users can be the difference between profit and destruction. Maybe it's margins that you'll save but keeping those users, possibly bad reviews, maybe market share over a competitor, there's plenty of reasons supporting older versions is not a definitive "waste."

Is it a pain to support old SDKs? Yep. But that doesn't make it inherently a waste of time to do so.