Seems like a reasonable breakdown, though I don't get the motivation to argue there will be less rather than more storms of both frequency and intensity. As you pointed out, we've seen no evidence of that. In fact we've seen increase in both frequency and intensity.

So why is this conjecture of less frequent but more intense storms even being made?

Wishful thinking, that we might be able to carry on destroying the planet for profit a little longer?

https://eric-bott.medium.com/forget-greenhouse-gases-ef857af9b168