There were scientists warning of the possibility of a Tohuku 9.0 earthquake before it happened, but they weren’t sensationalized - they were ignored.
You have to look at it on a case-by-case basis.
We now have multiple lines of evidence that we have underestimated the maximum quake possible on numerous faults, so it’s likely that there are others where this is the case.
On the other hand, the whole East Coast Tsunami caused by a volcano collapse IS sensationalized by the media and bad documentaries - it’s basically one scientist whose work has been debunked by the tsunami science committee as a whole, yet you still see people on FR excitedly talking about it.
“maximum quake possible”
again, I repeat - “possible” is neither “likely” or “certain”
Just as lots of variables in a math/computer model MAY suggest some POSSIBILITIES, among those variables are also possibilities that can change the conditions today, and change the values of those variables tomorrow.
Siezmic science is still in kinderagarten and even less reliable than wheather predictions.