At the same time, because of all that, he can't not be a villain anymore. Hell, his first bit was technically high treason. No eccentric Billionaire crap with that. Ship has sailed already. So, what else is he supposed to do? That's right. Rob banks, join up with an abusive father figure to get some payback against the FF, and the occasional wet work.
Everybody doesn't have to be a guy with a tragic past that coulda went either way. You need the bums. The nobodies. The why bothers. So the special ones can stand out. If everybodies special, then nobody is.
Trapster got a pardon for his high treason crime when he helped the Avengers foil Baron Zemo and the first incarnation of the Masters of Evil. He could have walked away then, but he didn't, despite his villainous career being a failure at that point.
Also why did that ship sail? Why did decide becoming a villain was a good idea in the first place? I'm not saying he needs a tragic past, but maybe a better explanation of why he is who he. If they aren't going to do that, they should just demote to him comic relief villain and stop putting him on the Frightful Four. If Trapster is just a bum, I don't see how he works as a villain, his gimmick just is not threatening. He doesn't really work as generic goon villain, one because he supposed to be intelligent and thus shouldn't be just a goon and two because there a villain thug villains who are far more threatening then he is. I don't see why we need so many bums and losers, given a character the occasional chance to shine doesn't diminish other characters. No one would want a super hero to just be a bum and nobody, why do we need so many villains to fill that role, just so the same A-list villains can continue to hog the lime light and continue to be over exposed? How does one decide why villains should be special and which ones should be nobodies? Villains like Magneto and Kingpin became "special" then they were revamped by Claremont and Miller. Even some obscure villains like Gladiator (Melvin Potter) got more of a push as a character, compared to other villains. What makes Gladiator more special then Trapster?
His life as villain brought all that unhappiness to him and we never got a decent explanation as to why he decided to become a villain in the first place. All that stuff should motivate him to change his life, not continue on a path that brought him nothing but sorrow in the first place. Unless he is a masochist, him staying a villain makes no sense. Its like he has some sort of anti common sense, even a total idiot like Rhino makes fewer mistakes then he does and Trapster is supposed to be intelligent.
Even most super villains are sane enough not to intentionally pick a fight with Ghost Rider and yet he decided that was a good idea. He wanted revenge on Ghost Rider for foiling a robbery, when most villains would happy that they survived a fight with Ghost Rider in one piece. Most Trapster's revenge schemes don't make any sense. Trapster wouldn't have been exposed to the penance stare if he hadn't tried to get revenge on Ghost Rider for a very pointless grudge. It seems like that experience should have scared him straight, at least a little, but other writers seem to have ignored it and the psychological implications it would have. If there is some sort personal demon that forces him to do these insanely self destructive things, that should be explored. To me Trapster trying and failing to reform would explain his actions better. At least his failure at reforming could explain why he continues on this path, he tried to change his life, but since he failed, he feels he cannot change it.
I do think the fact that Trapster seems determined to stay on this path, despite all the evidence saying it is the wrong path for him, needs more exploration then the reasons you have given, they just don't explain this level of insane determination to engage in completely self destructive behavior. If you read the novel story where Trapster tries to reform, you may think its a good story.
