Making first contact is a big part of winning reps vs pass rushers. But leaning to make that first contact leaves you in a vulnerable position.
Stand with your back to the wall and measure your outstretched arm. Have someone hold a pencil .0000000001 inches further than your arm measures. You can say it’s such a trivial distance but the facts are that never ever in your life are you going to be able to stand with your back to the wall and reach that pencil. It doesn’t matter how ridiculously small that distance is, you just flat out won’t ever be able to reach it without leaning forward.
Wingspan is important because having a shorter one means you are in a more disadvantageous position on every single pass rush snap than you otherwise would have been. If the guy you’re blocking has longer arms than you, he’s got an easier time establishing first contest and sitting in the driver seat for that rep. The OT with shorter arms will have to use footwork and body positioning and discipline to not lean too much and open himself up to counters while he chases making that first contact. It means you have to more of a passive/patient pass blocker since you need to wait for the rusher to get a small bit closer to you before you can strike, because being too aggressive means you have to lean forward to make up for your shorter arms.
Playing football is really harder. Shorter arms as an OT makes it harder. It’s really that simple.