I race electric on-road and we have a couple endurance races we run every year. We’re able to get upwards of 45+ minutes of run time without losing performance from some of our high capacity (8000mah+) batteries.
But we also run high turn (21.5t or 25.5t), and sometimes fixed timing, motors, so draw isn’t that significant.
My Losi Baja Rey running a 3600kv (beefy, high draw) motor gets 15-20 minutes of run time from my 5000mah battery depending on how hard I run it.
Run time really comes down to how high draw the motor is, lipo battery technology is significantly improved over the old nicad and nimh chemistries of the past.