True, but Crimson was arguably among the most popular of all of them and has the longevity, whereas Camel lost popularity and (as you said) Genesis became a pop band. Let's also not forget that Yes's 80s stuff is nothing to brag about, and especially compared to albums like Discipline and Beat.
No, they demonstrable weren't. Discipline reached 45th on the US Billboard, Beat 52nd. Drama was 18th on the US Billboard and 2nd in the UK. Nude, The Single Factor and Stationary Traveller by Camel placed in similar positions to Discipline and Beat on the UK album charts. Genesis may have turned into a pure pop band later on but they were still releasing Prog in the very early 80s, the period in which you claim that King Crimson solely kept Prog alive.
Then there's Rush, who I neglected to mention in my previous post. They were massively successful during this time and the material they released then had a profound effect on Prog in the years that followed.
And yes, Marllion was popular in the 80s, but they never seemed to do anything particularly innovative, as the majority of their sound comes from early Genesis.
Early in their career, certainly, but by Fugazi was a significant step away from that. Misplaced Childhood, their most successful album - one of the best selling Prog albums of all time - sounded very little like Genesis.
They are an amazing band, but neo-prog owes a LOT more to 70s prog than it does to Marillion.
No. The reason Neo-Prog bands that formed after the initial wave of bands in the early 80s are known as Neo-Prog bands is because they write music similar to the pioneers of that subgenre, chiefly Marillion and IQ.
Crimson was one of the few bands to really innovate at the time by incorporating polyrhythms, New Wave, and touch guitar, which as mentioned before has influenced many of the newer progressive groups that rely less on technical skill and more on ambience.
Yes on the polyrhythms and touch guitar, no on New Wave as I've pointed out. As innovative as King Crimson were during this period, the idea that they saved Prog is selling their peers of the time short.