To make it to the highest levels of play, any gear specialist will need to account for even those 5%-of-the-time scenarios. There are plenty of those 'rare' scenarios, so there is a low likelihood of experiencing the ideal case for every gear in a match. Therefore a gear specialist will need a ground intake to maximize value.
Think about it. It's finals. There's a gear on the ground in next to the HP feeder station. The robot gets fed a gear from the feeder station and inadvertently pushes the gear on the ground a few inches towards its airship during the trip back. BAM - referee raises the flag
[G27] Multi-Gear possession. Since it accidentally moved in a strategic manner towards the airship, the question of a YELLOW CARD comes up with the head referee. YMTC.
Still want to ignore gears on the ground as an alliance?
Plus, if you add 900's gear tracking vision system, a 2-gear autonomous is all but guaranteed.
Not only is a 2-gear auton about the potential for 20 more points, it also saves time - arguably the most valuable resource to high levels of play in any FRC game.