I don't think it is all doom and gloom.
The theme parks seem to be fairly popular this year as people aren't going abroad. The poor operations at Thorpe with long queues may do more to put people off.
Some did get scared off by the Smiler incident, but many people accept the park put in place new measures. At Drayton Manor, although the operations weren't correct in terms of monitoring, the guests actions on the ride did play a part, but it could have put some people off rapids rides as there was a death.
In this case at WMSP, it only seems to be reported on local news I don't think it will affect many peoples decisions on visiting theme parks, if they are the sort who would be put off by bad news, then I expect Smiler and Splash Canyon would already have made their mind up.
I think given there has now been two incidents on rapids where it is reported the guest was at partly at fault this may be causing parks to make other decisions on whether guests can be trusted on rapids, so as Roy says the future for rapids rides may be bleak.