That assumption is a flaw in your process. Lots of people aren't going to wait that long to take feats. Feats are quite often better than pure stat bumps and come with a +1 to a stat as well. People will be taking them at 4th level.
How does the rifleman's creed go? "This is my rifle. There are many like it, but this one is mine."
"This is my scenario. There are many like it, but this one is mine."
In other words, the fact that there are other possible options does not invalidate my results. If Lowe and Max took shield master at 4th level, that would just mean that they have a lower chance to hit or fewer hit points because they didn't increase ability scores.
Don't like my scenario and results? There's nothing I can say or do. If you have a better way of doing a comparison other than restating your opinion feel free to do so.