Everything is in Marvel's favor.
Unlike DC, even if Captain America 3 totally bombs, they can absorb the hit and have multiple other brands. There's a reason they announced ELEVEN movies coming out from now. If one or two underperform, the rest can salvage it (like The Incredible Hulk... and even THAT made enough money to be profitable). If they win the weekend, then you have Marvel's solo Captain America beating DC's two top heroes combined. It would be a tough sell, sure, but we're living in an age where Iron Man 3 has made more money than any Batman film ever has and Captain America: The Winter Soldier left Man of Steel's gross behind in the dust (and Thor 2 came really close).
DC, on the other hand, has history against them. Man of Steel is still a "certified Rotten" movie with critics, despite making money, but it divided more than united DC fans and Superman fans. Apart from Batman (and his track record is iffy too), DC movies just haven't come close to the level of quality fans would expect. From Jonah Hex to Constantine to Catwoman to Green Lantern, DC has shockingly done little to match the quality of their animated Paul Dini/Bruce Timm universe.
DC has the most to lose. They put all their eggs in one basket. Nobody will care that much if Captain America 3 underperforms, since it's the third installment in a series and the other movies will be unaffected, but the ENTIRE DC universe in film apparently hinges on this one movie. Even if Batman v Superman: Dawn of Bad Subtitles isn't bad or even if it WINS, it's profit will still be undercut by another quality comic book movie the Marvel faithful will be eating up instead. It's a lost ticket every time a fan picks Captain America over Superman and Batman, and the vast majority will not go and see both the same weekend, if at all. If the cost of making this film just doesn't warrant the investment (and you bet it'll be uber-expensive), it hurts them long-term and it hurts their properties going forward long term, even if they gain a short-term victory.... IF.
Personally, I despised Man of Steel. And I say that as a passionate DC fan of the comics who grew up watching everything from the 40's Superman cartoons to the Superfriends to the modern Justice League.
But Captain America: The Winter Soldier was amazing.
A timeless, heroic, iconic hero of American truth and justice, trying to find his way in a modern, morally ambiguous world of tough choices without compromising his integrity... The Winter Soldier was a far better "Superman" movie than Man of Steel was.
I know which movie I'll be seeing that weekend.