I've never been to Fenway. There's a couple points where I might have managed to scrape the money together and go but was daunted by the reputation of the tiny seating. It's no great mystery that people are bigger than they were 100 years ago, and I'm big for a modern person, clocking in at well over 350 pounds. There's no way I could actually visit Fenway and take in a game without leaving with a significantly gimpy gait, either from the constipated seating, or from having to stand for 3-4 hours with little relief. The place just isn't built for me.
I'll tell you all this right now. A 50,000 seat stadium, if they could find a place to put one with T access, bigger seats and all the amenities, would have 50,000 fans paying just as much as 30,000 fans pay right now, to take in those baseball games. Demand is sky high. It's not a question in my mind. They would make more money if they abandoned Fenway, at least they would once the fan revolt died down. They are tying their wrists and ankles together revenue-wise sticking with history over good business practice.