Not 30+ years of war-driven evolution.
And where is it ever stated that the galaxy has been in a perpetual war for the last 30 years?
Because the crawl indicates:
Luke Skywalker has vanished. In his absence, the sinister FIRST ORDER has risen from the ashes of the Empire and will not rest until Skywalker, the last Jedi, has been destroyed.
To contiue from there we have to look at the canon that was created alongside of the film.
The book Before the Awakening states the following about the First Order:
The First Order is a remnant born of a war thirty years gone. Yes, they persist, yes, they continue, but by all accounts they do so barely. They are, at best, an ill-organized, poorly equipped, and badly funded group of loyalists who use propaganda and fear to inflate their strength and their importance.
The fighting continued for a year after the Battle of Endor, coming to a head at the final battle at Jakku. After which:
In the month since the Battle of Jakku, the Empire has attempted no further large-scale offensives. Sources report all Imperial vessels within the Core and Inner Rim staying within the boundaries defined by the treaty. A few prominent members of the Provisional Senate have speculated that the New Republic’s war with the remnants of the Empire has finally come to an end and that a final surrender may be imminent.
The Empire formally surrendered and signed the Galactic Concordance peace treaty.
From there the New Republic and Empire were at peace for decades. It wasn’t until Kylo and the Knights of Ren destroyed the new Jedi Academy that the First Order rose to power.