From what I recall reading over the past several years, the “locals” in Venice were being priced out of the city. Housing was one such area of concern, and now some reside on the mainland and commute in to work there. But during peak travel seasons the number of tourists can make commuting very difficult too.
As a result, Venice instituted a couple of measures, though I have yet to read how successful they were. One was banning large cruise ships from the historic city center (I forget the name of the canal involved). Anyway, I was never clear on how that was expected to help meter tourism, as compared to other expected benefits like protecting the buildings, lessening erosion, etc.
Another measure was instituting a daily fee for day trippers during peak seasons. While it earns extra revenue for the city, and maybe they will use that money to try and improve the situation, I am not sure how much impact it had on the number of tourists.
But as others have mentioned, tourism is a major source of revenue for Venice. I am sure there were a number of places that had “a good week” due to the wedding.