Of the examples you are talking about (Cthulu, Mutants and Masterminds, Traveller, Deadlands), three are already dead, and the fourth (M&M) never used classes, used levels very differently, totally revamped the damage system, and in its present edition doesn't have feats or the six attributes and even changed much of the terminology and major aspects of the d20 resolution system, etc.
It has a separate powers system, but that's all.
No, it was released in 2003. They were already ditching d20 long before 4e was announced, and not because of licensing reasons:
https://www.peginc.com/freebies/SWcore/MakingofSW.pdf
Maybe I'm just bitter about d20 Fading Suns, but I feel like most of these failed, or at least turned out to have a niche audience without broad appeal. The sheer number of games that were attempted but didn't turn out all that great (or not good enough to last) should be a warning sign. Let's not forget that Wizards of the Coast even abandoned the d20 system -- first with SWSE (and SW Revised was one of the better d20 conversions) and then with 4E. The games that made it work best (Mutants and Masterminds and Spycraft and, I guess, Pathfinder) were not shy about changing the rules to exactly meet their needs.
Basically I think it's backwards to start with a system and then adapt it to a genre or play style. The best games start with a very specific play experience and build towards that. This is a definite weakness of any "universal" system, but systems designed to be universal from the beginning usually weather it better. Even Savage Worlds has certain genres and play styles where it does not work well (for example, supers; procedural mysteries; deep social intrigue; hard sci-fi). So trying to adapt 5E to all kinds of other genres will probably lead to tears.