This team and this town could support a 50,000 seat stadium easy. Money's there, fan interest has *always* been there, sponsorships and financing are almost definitely there, all that's been missing is the, you know, stadium.
I'm 6'5", 350+LBS and built like a linebacker. If I lost all the weight I should probably lose it'd only get me down to about ~270 LBS. I will never go to Fenway. I can't sit in ordinary theater seating, I need special accommodation for college auditoriums, and I have to buy 2 tickets to fly coach. If Fenway's seats are even smaller than that I'd have my choice of doing hella damage to my knees and annoying the people behind me by standing the WHOLE game, or doing similar damage to my own hips by trying to pretend the seat is big enough for me. I'm not paying that kinda money to be that uncomfortable just to sit next to a bunch of drunks and watch a game I can watch on TV. Any 2 of the three (the drunks, the discomfort, the cost) and I'd be OK, but not all 3.
I don't think destroying Fenway is really necessary. If nothing else, it's a historic Massachusetts landmark. If you ask for a famous building in Massachusetts or Boston, Fenway's probably the first guess of most folks. It, or parts of it at least, should really be preserved for history, and maybe you could even break it out of mothballs for a few exhibition games or something just to keep the tradition alive. But seriously, get a new ballpark, Sox! I want to be able to take in a game AND be able to walk out of the stadium when we're done, is that really so much to ask?