It would be more efficient with ems, but we can’t make ems yet. Technically we could already colonize space; it’s expensive, but still, it’s closer.

Think about why old-world people colonized the Americas (and everything else they could, anyway). The basic cause was space and resources. Of course, with current tech we can extract much more value and support a much larger population in Europe than we could at the time. But even if they anticipated that, it still wouldn’t have made sense to wait.