I have thought it has to do with the multi-point touch functionality.
It was never necessary when working with Controllers. It showed up at the same time as multi-point touch.
A toggle to disable the focus/selected separation should also reduce touch to a single point.
Since you can touch 10 tracks at once, which track should get the focus/selection. If every time you touch a different track to turn on mute or solo, the track shown in the Inspector changed, it would be a serious problem.
I did find this selection/focus scheme extremely confusing when it was first introduced. It caused me to change the fader on the wrong track many times. For me, it was the most confusing when I was working on an automation envelope in a track, but the track had not taken the Selected role.
At this point, having used it this way for years, it no longer confuses me. I don't accidentally change the wrong track's parameters.
One thing I do is set track icons and change track colors. These can be visible cues as to which track is currently in the inspector without having to read the label at the bottom. While I feel I understand the reason for the separation between focus and selection, I wonder if a better way of handling the division between the two won't present itself in the next few years. Personally, I can't think of an easy solution. I think many people don't realize how complicated it must make the application to have a possible 10 threads that can run concurrently (one for each finger). It makes the threading for the finding of the VSTs on startup seem trivial. Or the threading for the drawing of the wave-forms. Notice that communication between the main thread to the drawing thread was just added to advise the drawing thread to pause work while the main thread leaned heavily on IO for playback/record purposes.
I must say, the touch nature of the app is REALLY intuitive. It's so cool. Sometimes, I have trouble with touch. Consider the flyout EQ. I have trouble adjusting Q with pinch. Touch works fine for gain and frequency, but I've learned to go to the nob to adjust Q.
In general I think touch is awesome. It is especially great when the leader of the band you recorded is sitting at the desk with you and she can twiddle the nobs and faders at the same time you do.