I am in the garage door business, so I can speak to this with professional experience. Range differes due to weather, electronic intereference, and other factors. The FCC also put limitations in place over the years due to zero lot line properties as well. A positive side effect is the range limitation to criminal activity thru "grabbing" of codes. Another timing factor is the specific security system employed by the brand of motor, in conjunction with the other factors that limits the range.
I tell my customers that you should always be stopped in front of your garage door (so you don't drive thru it) within 25 feet, and that you may need to hold the button for a couple seconds to allow the security (e.g. rolling code technology) to confirm that you, in fact, are using the authorized remote control (be it the car's built-in or a handheld) to activate the door. Pushing the button (remote or built-in) several times is actually just contributing to confusing the security feature of your operator. Push and hold is better than push, push, push. 75 feet is the usual range...anything beyond that is more than you need!
It may take a couple seconds to allow the button to activate and approximately 12 seconds for the door to open...but waiting 15 seconds for the door to open completely is not a long time. You also don't risk the chance the door is not open fully and you slide on ice/rain slick asphalt in to the door...we make extra money in the winter from this exact situation.
We have seen that some cars develop problems that interfere with the range and operability of the built-in remote, and even interfere with the handhelds...if any part of the cars' technology sends out signals it is not supposed to then the remote operation will not work properly. Always test a handheld remote first, and determine the maximum range with the garge door closed...then pull the vehicle within that range and try the cars' built-in without the vehicle running, and then try it again with the car running and try the handheld too. If there is any inconsistancy with the car on, then you are having issues within the vehicle itself. Try it on different days and you will notice a difference as well...those other factors.
Hope that helps.