The Romulans could well remain the isolationists they've almost always been shown to be.
But the alternate Romulans are different than those the the Prime timeline, in so far as being not as isolationist.
nuChristopher Pike recognized Nero quickly as a Romulan, something the prime universe Pike of the same year wouldn't have been able to do.
Doesn't The Old Spock finding a suitable planet for the Vulcan to Re-Habitate and Continue their Existence...
Would that not make SPOCK (Past-Leonard Nimoy) the new founder of Vulcan Philosophies and existences.
No, that would make prime Spock their real estate agent.