The other thing to consider is that for Pay-As-You-Go folks, JJ hit them in the wallet either late last night after the buzzer, or early this morning. Those tickets, who are probably mostly STHs who use them on their own and might sell occasionally, would probably just be coming on the market this morning, since you can't sell a ticket until you pay for the ticket.
I got an email after the last round concluded, offering STHs more balcony tickets (probably high and on the ends) for the SCF at 400/450/550/700. I'm 99% sure those got snatched up fairly quickly. Fees were not mentioned, and I have no idea what the rules on resale or transfer of those tickets would be. The cheapest ticket I ever saw for Game 7 was, oddly enough, a "blue dot" ticket directly from TicketMaster - $699 for a solo seat in the balcony, but about $800 with fees. And you had to pounce on 3/24 - which is when tickets went on sale, I'm guessing.
Box office tickets won't be cheap or plentiful, but if Fenway says they were there for Game 5...who knows. The prices are nuts, but...if you put it in perspective, it IS a once-in-a-lifetime opportunity. Assuming a 32 team league with every team being equal and every game being 50-50, we make the SCF every 16 years. The series goes to 7 games 31.25% of the time, and game 7 is a home game half the time. That means you get a Game 7 at home once every 96 years.