> Factors like these mean in prior decades the total damage costs may have been more similar to today's than they appear but a lot of the damage data we gather and report now wasn't counted or gathered then

This is definitely part of it. Another part is that people live in more at-risk regions now than in the past (Florida is a great example, population has more than 10x'd since 1950).

Ultimately, the way we think about it is no matter what the underlying cause, weather-related damages could be significantly reduced with better data/forecasts