Airlines won't do that, and here's why. As you correctly point out, the seats in the back of the plane are horribly, awfully cramped, making it impossible for business guys to manoeuvre their laptops without elbowing each other. This is intentional, because it induces those businesspeople who are both sufficiently desperate
and have the money to spend, to pay for the much higher-margin seats at the front of the plane.
That's the main reason why flying coach is such crap.
So, you might think that removing 1/3rd of the seats and charging 33% more would be a revenue-neutral proposition, but it wouldn't be. Passengers who currently fly at the front of the plane would look at the cosier seats in the back and think "hey, actually -- I can live with that". Business-class passengers won't pay for seats at the front of the plane unless the seats in the back are sufficiently awful. Because the seats at the front of the plane are much higher-margin, the airline would lose money as a result.
(This isn't my own home-brewed conspiracy theory; this is based on reading Harvard Business School case studies. The things one learns whilst studying price discrimination theory during an MBA...)