Marvel chose those two properties at the time cause they were a studio with money but no big properties left to fund productions for. WB has been in a similar situation only they chose 2 different properties(followed by various others). Safe to say marvel chose their two biggest names at the time, if there were as bold as people suggest then they would have chose antman and the raccoon, if they had spidey and xmen(something WB has in it's own way), they would have chosen those. Granted hulk fell short and they put it on the back burner...that is until they found their golden ticket in the form of 'tie in'.
That is also to put into question just how much more success it to be found in selling the audience a linked universe to rather tying everything to your biggest brand. If Heath or Bale showed up at the end of Lantern the way Loki or Stark has shown up in various stingers, would it have made 'Cap/Thor' money and been a 'success'? Hard to say, the GA is a fickle thing imo.
And please stop with the, they didn't have enough success to make a solo superman sequel. The film made a crap ton more than just about any cbm start up that has become before it(minus spidey) A good deal more than Batman's start up(and he's the/thier biggest). It's an opportunistic statement at best and people are jumping on it any chance they can. Did anyone say Marvel didn't have enough faith in Cap/Thor before launching the big crossover? Or did people just see the 'genius' it in... I for one have never understood why people think MOS was supposed to make a crap ton more money than it did. I mean I get why people expected TDKR to but no one expected Begins to. Yes it's superman but what did the last superman make(also superman)? I see why everyone expects the next bond film to make a crap tone but who expected that of Casino Royal?
If anything the studio see's alot more pros to going about this venture than the traditional sequel route. Why let marvel have all the novelty success? So fans can continue to rub it in their faces? The DCU land scape will be alot more viable after a BvS film than a MOS2 film, period.
Just has it has been for Marvel. There was no guardians after Ironman 2 but after avengers? It's viable. If anything WB might not be so confident in simply relaunching batman post nolan and bale, and to do it this way almost guarantees massive success. That statement I can get behind.
The internet tends to see recognizable names and vision tends goes red. The goyer effect if you will.
I partially think this has something to do with the serialized format of TV. Countless interviews with the creators talking about all the 'live' adjustments they've made based on fan feed back and such. Then there is the ravager situation. Sick of Laurel, well here's the new love interest..etc. Movies don't tend to have that luxury.
Safe to say as great as the show has been, it wasn't all that it is in it's first 2 and half hours but rather the entirety of it's run and due to it's build up. An IM tv show would no doubt enjoy the same benefits.