We know from linear and rotational acceleration that F=ma.
Thus a constant speed is achieved (stable) when the forces are equal at a point on the load line.
Where it is unstable is below the Tmax. This is a boundary conditions where Tload < Tmax and where equal determines RPM with no acceleration force and constant velocity. The other is starting up if the load is between Tmin and Tmax, it wont start up, so startup caps and coils are used to boost the motor current until a speed where the transfer switch has about the same torque as Tmax
Otherwise the motor would never start up and the load torque must be less than the starting torque to start up.
Now the slip effects cause this low torque at 0 RPM and this loss of torque declines with rising speed ( ie torque rises) such that when it generates BEMF which ends up limiting the voltage drop internally and thus current drops with available torque.
Past this peak, Tmax Torque is now dominated by BEMF as the slip effects are now minimal but depends on the magnetic design.
Just like a voltage regulator with resistance. Voltage drops with more load current V=Voc-IR or like a spring in the linear stable part of the curve that deflects down x with force in the same direction, F for x=F/k for some spring constant, k.
Thus we see there two factors that reduce torque in AC induction motors.
1) Slip frequency which demands a boost circuit for startup and
2) back EMF , which generates a voltage opposite to the applied voltage and for Induction Motors it becomes 0 torque at some integer ratio of the line frequency and number of poles.
This optimal peak ratio of RPM / max RPM depends on the motor design and there are standard torque curves that differ from your example.
The maximum power is at a higher RPM than Tmax since Power = speed * Torque when using MKS units.