No one outside of comic book fanboys KNEW about Iron Man! The Hulk, sure, but he had what, two reboots of crappy movies, and Spider-Man had like two good movies before it all went down the toilet---and wasn't even connected to the larger Marvel movie universe.
And technically, the got started with Blade.
As for Cyborg, yeah, a few 8 year olds know him due to the animated shows. Which, by the way could have easily gone the other way and had animated shows featuring PG, thus making 8 year olds know her better. So it's a rather pointless argument. DC chose to go with Cyborg for their diversity quotient instead of going for the girls and women, and that's that. But he's still a third stringer. They can make a movie about him, but it won't do very well. In fact, it will probably do less than the recent Robocop, which is a much more well known property than Cyborg.
Also, you seem to be ignoring GoTG, which was totally unknown to the public, and even little known to the comic book fans. Gee, let me see, that must have done terrible because no one knew about it, right? Oh...wait, it took the box office title for the year, outpolling Captain America...
Cyborg was a terrible idea because he's boring. And angsty. Two things DC does very well these days. PG OTOH has potential if done right, and could pull in a much larger audience for any number of reasons. The chance to do MoS right for example; to finally make an upbeat, classic Superman story that they seem incapable of doing with Superman himself.
And I gotta say anyone who thinks Cyborg had a much bigger role in NTT than PG did in JSA has probably never read either.
no, that is not how marvel got their start. marvel got their start releasing their most popular heroes on the bi screen like iron man, hulk and spider man. it wasn't until they got their feet on the ground that you started them taking risks. dc is doing the same in their own way.
nothing you've said about cyborg disproves the fact that more people outside of comics have been exposed to cyborg then power girl. he has more outside revelence so going with him for a solo movie over pg makes sense, no excuse is going to change that fact.
stop, just stop. the amount of times superman alone has been mind controlled dwarfs pg's. and define not close. cyborg debuted 4 years after she did in 82. yet the only thing she has over him is one solo, which you even said was abysmal. other than that, cyborg has been a much bigger presence among the titans than pg ever was among the jsa. frankly i'm done talking about cyborg at a pg forum. the point is pg needs to build up her profile, which is tough to do when she already has to compete with herself(supergirl) and her famous cousin(superman).