Unfortunately with Broadway's state, it is a mix of a number of dire situations: 1) Affordability - I know people that would come to the city annually, and see 12-15 shows in 8-10 days, then their budget for shows would remain the same but they would only be able to see 4-5 now its 3-4. That as well as the overall increase in expense to spend a week or 10 days in the city between accommodations and food and everything has become so out of budget, that many are choosing Tennessee road trips, or European vacations for much the same budget.
2) What is being produced. I know that I have said this before on here to much ridicule, but a large portion of the "tourists" and visitors to the city are not enjoying the hyper-political topics, and ones that feel agenda driven or lecturing. In the "middle-America" areas people, want an enjoyable evening, some spectacle, something welcoming. A couple of friends of mine who are not on "budget" travel and would frequent 14 plus shows, this spring went and ended up seeing 5 shows (including 2 shows they had already seen before). There was nothing that really that was interesting, they were not one bit interested with the Cats revival. They also felt that what was being produced also just felt, meh. Revivals like Chess fell flat in many areas for them. They enjoyed Ragtime and loved Death of A Salesman. But I hear over and over from people that they with Broadway producers would put something on that a "middle-America" would enjoy - and no, they are not a simple group of people that will buy into a jukebox musical or thrown together revue of some singers life.
3) Safety - another topic that I have been ridiculed before about, but a lot of visitors, do not feel safe in the city. This has been increased in the last 5/6 years, but they don't and therefore many of them are choosing areas that are safer, and going to see some concerts or theatre while there.
4) The cost to produce on Broadway vs West End or Toronto has become insane. They need to deeply restructure their model, and I don't know if the easiest and quickest model is to have theatre owners more influencing what goes into the houses and what's created.