Innovation sometimes means risking your life. I'm grateful there are people willing to do that to advance our capabilities, because I am not. However, I'm not convinced that eccentric billionaires paying a quarter of a million dollars for a vanity trip to a maritime graveyard, qualifies as innovation. Nor do I believe that it deserves a multi-million dollar international rescue effort. All five of these people knew and happily accepted the dangers and risks and should have to live (or die) with the consequences of their decision.
I have tons of sympathy for their families, but in my opinion, this is no different than climbers who go missing in Everest's Death Zone. Those people don't expect a rescue because they know it is near impossible and puts others at risk. Extreme deep sea expeditions should be treated the same way. To be fair, I don't know that the five missing would have expected or even wanted this kind of rescue effort, but it's something countries will have to discuss in the future as extreme tourism seems to be on the rise.