I think it likely that the Romulans, and much of their culture are pretty much how the Vulcans were before Surak.
But it's implied that Surak saved Vulcans from a disastrous situation, where they were at each others' throats. Romulans seem to have a far more functional society than that. They couldn't be a powerful empire otherwise.
I think Romulans are more like the original Vulcans than Vulcans are, but that they've found their own accommodation with their personality issues, without needing Surak's solution.