I stumbled upon the thrust curves and what you say below is correct and shown by the thrust curve graphs.

Well said, and exactly right. the simple thing, that a few have spent many paragraphs explaining, is that HP really has all the information you need for acceleration potential for a car, at any speed.... after all,
acceleration = power/(mass x velocity)
so, if you maximize hp at any vehicle speed, you maximize acceleration.
it takes all the guess work and calculations of using engine torque, with gear ratios , rpm and vehicle speeds , out of the calculation. just maximize HP and you maximize acceleration and there for, torque at the rear wheel or better said, force to accelerate.

this is why shifting past HP peak is so valuable to understand and see. because if the hp post shift is less that before that shift, its better to stay in gear even though HP is falling off... (because its better than the much lower HP value post shift as shown by Bill's thrust curves)