Cut the kernels off of the corn into a large bowl. Using the back of the knife, scrape the sweet corn milk from the cobs to extract about 3 tablespoons and add it to the bowl. Set aside.
Cook the bacon in a large skillet over medium heat until the fat renders and the bacon is crisp. Remove with a slotted spoon to a paper-towel-lined plate and set aside. Add the butter to the skillet and when melted, add the celery, bell peppers and onions. Season with salt and pepper and cook until the vegetables are soft, about 15 minutes. Add the milk, scallion whites, garlic, tomatoes and corn. Cook until thickened, 10 minutes.
Serve garnished with the scallion greens and reserved bacon.
When cutting the corn off the cob, place a small bowl upside down in the larger bowl. This elevates the corn, making it easier to cut down the cob and catch the kernels and milk in the large bowl. More milk can be extracted from the corn if the first cut is shallow, leaving more of the kernel on the cob to scrape off.