I heard that input GPIO is unable to sense any input when the input current is too low.
Either they were were wrong or you misheard.
Why are you simulating a rubbish circuit? Switches should be wired between the input pin and ground. Then a pull up resistor goes from the input pin to the processor's supply voltage.
As mentioned the higher the pull up resistor the more susceptible is the pin to picking up interference and giving you a false reading.
It is a compromise, you trade current you use when the actual button is being pushed with immunity from interference. When you are not pushing the button you get negligible current drawn and changing the resistor is not going to affect this.
In practice the internal pull up resistors of 30K are considered weak but will work in quite environments. A value of 10K is used if signals have to go off the board and 1K to 470R is used in hostile environments like a car.