If you cook it for a long time, you'd reduce it but a cup of wine only has about 150 calories and I'm assuming that's not for one serving. Whether it reduces substantially, or not, is a minimal difference in overall calorie count (if the cup of wine goes into making 4 servings, then it's fewer than 40 calories w/out evaporation and 20 calories if half evaporates--what's 20 calories, just leave an extra bite on the plate?).
This might be helpful for you to compare, based on how you're cooking:
The total calories will be reduces, but not by a significant amount.
Alcohol calories = Sugar/Starch (4 cal per gram) + Alcohol (7 cal per gram)
The first part ain't going away. Unfortunately, that's where the majority of the calories from wine come from. The second part can be reduced, but it takes a lot of time get cook out alcohol from a dish. Just to throw a number out there, I wouldn't bet on anything much higher than a -10% reduction.
You are correct about losing calories from alcohol but not from carbohydrates. Calories from the alcohol itself will be reduced to the extent which you evaporate the alcohol, which is dependent upon how long you cook it.
But I believe you are incorrect that most of the calories in wine come from carbs. Most of the calories actually do come from alcohol. It's possible that an extremely sweet wine or a very low alcohol wine would be an exception.
A 5 oz glass of wine has about 12-14 grams of alcohol, so there is the potential to reduce the calorie count by 84-98 calories (if you reduce it very fully for a long time). The same glass of wine will likely have only 1-3 grams of carbohydrates, contributing far fewer calories.
So to the OP - YES calorie count from wine can be significantly reduced by cooking the alcohol out. BUT bear in mind that the alcohol is not cooked off as quickly or fully as cooks have long been led to believe.
Oh, but of course, CBD; I never think about the calories in alcohol, just in the carbs. I'm seriously deluded when it comes to that subject. Personally, my body seems to love/hate carbs, and I've always been able to drop pounds by reducing my carb intake, but never by eliminating my alcohol consumption, just reducing it, either in the pan but more in the glass.
Alcohol is reduced in percentages according to length of time spent over heat; chowser's informative link below states percentage of alcohol reduction; useful for approximating calorie count. It's a minimal caloric reduction at the top end; the OP would be better served by reducing calories in other areas, and assume wine as an ingredient in a dish is not going to be a significantly hinder weight loss.