Who set the "ideal"? We are nowhere near the limit of what we can provide for, and we are staring down a dire global population implosion in the next 50 years or so.
Who would want more people? Me. Any time you feel there are too many and somehow find the courage of your convictions...
The maximum we can support isn't the number we wan't to live in. We don't want our country to become an endless sea of humanity. The goal is the desirable population, not the maximum possible population. You have to be a moron to support the latter.
Feel free to move to India, since you find that idea so attractive.