To say they would not have come around may well be inaccurate on my part I am sure that CBM or Superhero movies would have still existed as evident by the non DC/Marvel movies however would they have ever have been such big productions as we see today without DC influence and demonstrating the level of interest a big budget superhero movie can create? Impossible to say of course simply because we never have a alternative universe to compare ourselves too like in the comics lol. The thing with reboots though is they are made usually because the studios feel like it is a safe bet and are able to milk the original movie fans by relaunching a new version rather than for the love of the original movie or to make art. Still sometimes we are given a good reboot I guess but more often than not they do not equal the original or even attempt to surpass it.
And we're talking big budget films with big stars.