It would be catastrophic for Turkey. Even modern day Turkey, with all of its current holdings, isn't resource rich in terms of oil, gas or whatsoever compared to its neighbours yet Turkish economy is stronger than them because it has industry.
Turkey was lagging behind in infrastructure, industry, education, technology while the monarchy was falling apart. Ataturk was the person who revolutionized everything about the country from civic laws to education system ( for instance first educational geometry books for schools were personally translated by Ataturk from French to Turkish). Ataturk was the person who started Turkish Industry and freed Turkish women from the chains of sharia. Ataturk's revolutions are like Enlightenment Age-Industrial Revolution packed in 15 years.
BUT Ataturk's ideas were not publicly supported at the time. In fact, Ataturk's revolutions were completely against dogmas of any religions and culture of obedience that ruled minds of people; he enforced strict secularism and positivism on his people(unfortunately, he couldn't entirely succeed. Otherwise we wouldn't be dealing with Erdogan).
Ataturk was able to do all these things for one specific reason: Every nation who wasn't ruled by foreign powers has their state cultures. Turkish state culture is strictly militarist. For instance, German state culture is diplomatic, they have failed horribly every time they tried to go militaristic route. In Turkish state culture, military is the most respected institution. As the triumph Field Marshal of this war, Ataturk had unlimited credibility in the eyes of Turks. Make no mistake, Ataturk was even offered to become the monarch but he refused. He chose to become the champion of enlightenment in the lands ruled by obscurantism and dogmas of religion not for himself but for his people.
If Greeks won this war, Turkey would not be much stronger than Syria or Iraq (give or take for their oil vs Ottoman Turkey still had intellectuals, although none could do the Ataturk's revolutions).
I saw that it's been argued that Turkey could enter WW2 if Greeks won this war, one can only think that because Ataturk reformed Turkey. If Turkey lost that war, he wouldn't be able to do such reforms because he wouldn't have the credibility of being a war hero in a nation whose state culture is traditionally militaristic, and consequently Turkey wouldn't have the same industrial capacity.
In addition, even one of the Erdogan's biggest treason is defaming Turkish Military. Turkish Military does not only serve to protect the nation from outer threats but also serve to maintain the order of the nation. People do so much fuss about Turkish Military Coups of the past but Turkish Armed Forces never did a coup to establish a dictatorship. Keep in mind that Turkish Army recruited its officers from the age of 13 into Kuleli Military High School (a boarding school where children can only see their family during national holidays-new year's eve-summer) and raised them until they graduated from undergrad - grad school levels. Officers of this tradition and spirit have no understanding of using military power for their own good.
Whenever Turkish Army did a coup, they always removed politicians who posed threat to the greater good of people or secularism, and restored civilian political will right away.
There wasn't a coup like Greek Junta 67-74 which ironically ended when Turkish Army went on a trip to Cyprus to protect the Turks living in Cyprus, if you try to come for this, know that Greek Junta staged a coup in Cyprus for enosis supporters (go read what Greek Cypriot President Makarios says about that coup), and Turkey just fucked them up, and they fell apart. Greek Military Junta ? They obviously did not have the balls to declare war considering Turkey wasn't fighting on like 3 other fronts against superpowers.
Turkish Military coups never turned into dictatorships, coups were executed in order to restore the order and returning power to civil will was always the goal in the end. I think longest, Turkish Army ever took was 2 or 3 years after a coup to restore civil order; even for that time, it was publicly known that civil order would be restored.
Make no mistake by confusing that with 2016 coup attempt. When Turkish Army did coups, they always executed it when everyone was sleeping, and all command chain was in accordance. No political leader could go against. That coup attempt is likely to be Erdogan's plot to grab more power or a pathetic attempt by religious idiots called Gulen Movement Erdogan previously put into army as "his man" but later had a fallout with. I mean they tried to make a coup with 74 tanks and 246 armoured vehicle in a country that has 2,445 active combat tanks and 7,550 armoured fighting vehicles. Literally, one of my grandfathers is a retired paratrooper colonel (albay in Turkish). He simply laughed at "coup attempt" being aired live on prime time (He actually actively served during Turkish operation to Cyprus).
The world would be a better place.
One of the biggest virtue, even in warfare, is respecting the enemy. Go look at what Ataturk said about Anzac losses at Dardanelles Campaign of WW1, that might help you cure your dishonorable peasantry.