Even the max energy above is miss-leading, that's if you get to peak weight immediately and stay there, no letoff and no build up. You move the string 1/8 of an inch and you are at 70lbs, at full draw you hold 70lbs.

When you factor in the force draw curve its actually much lower. That's why lower let-off bows are generally faster than high letoff bows. More energy is stored.

To get faster you have to increase the power stroke, two choices, longer draw, shorter brace height. Neither is good.

Or you have to find a way to "create" energy, more than you put in.

Given how bows work, we are close to the limit, now its time to make them quieter for better efficiency (which gives a bit more speed) and more shootable.