I have flown this EXACT route several hundred times in 37 years, and no prudent aviator is going to ignore the weather in this region.
Sorry to be blunt, but anyone who has ever penetrated an active thunderstorm (for whatever reason) will do whatever it takes to never do it again.
Provided they survive their first encounter.
The Old/Bold rule.
At this point, this would seem to sum the whole thing up nicely.
The radar returns showing CB tops above 50,000 feet along their route could easily put them in an impossible situation.