You are focusing on the wrong part. Its not about doing the steps to travel a uniform distance, its about doing the steps correctly.
Notice how he always backs up to the same place he started before doing the next demonstration. Notice how he always ends up in the same place at the end. The distance he travels on each demonstration is approximately the same. Which is why he backs up the same distance to restart. I have done these in wrestling class, bjj class and MMA class. Only, we usually do them either in lines across the floor or in a big circle, everyone following each other.
Now, if he would do 3 of those in a row moving forward, then turn around and do 3 more back towards where he came from, he should end up on the spot he started. However, if in one of those 6 repetitions, he left the penetration step out, the distance for that rep of the drill would be shorter. If he didn't bring he trailing foot all the way in front on one of them, the distance traveled would again be different. But, its not so much about the distance being uniform, its about doing the drill properly, taking all the steps correctly.
Kata that are designed to end in the same spot are only taking advantage of the fact that when to do the same technique as a drill, each repetition will travel approximately the same distance. When I did boxing footwork drills, most of my forward steps were about the same length. If you are trying to work the legs, by using a lower stance in your drills, it defeats that purpose to rise back up after the first repetition.
Ending on the same spot is supposed to help you know that you are doing each technique correctly. It has been expanded to be some magical source of power, and a point to hold over someone else and into a lot of other things. But really, its just recognizing that if you do the same advancing technique 3 times forward, then turn around and do it 3 times back... if you did the drill correctly on each repetition, then you should end where you started. If you don't then you did not do all 6 repetitions the same.
Should wrestlers not practice their footwork for their shot, because the other guy might not be that exact distance away?