For many lakes, I donít think there is any question that ice fishing puts on a lot more pressure than open water fishing.
Many people spend entire weekends on the ice. It's like camping and fishing simultaneously, and each person has two lines in the water the whole time. Not many people ice fish alone. Contrast this with open water, where many people fish alone. They aren't out there the entire weekend either. They at least come off at night for the most part.
You can often fit a lot more ice fisherman on a lake at one time. If you have a spot to park your fish house, you're good to go. There are only so many parking spaces available for boat trailers, and some of those spots are taken by people who won't be doing any fishing (partiers, skiers, tubers).