You have yet to make a case that the straight-down-Elm really was a better path. Being "viable" doesn't cut it; you have to show that it would be clearly superior. Clearly superior, that is, on the basis of 1963 political considerations rather than what you'd like to think.
I've already noted that "there's little room to argue that the Elm-direct route would have resulted in a faster limousine," and I've provided the evidence for this. You can't deal with any of it, so you ignore it.
Why wouldn't it be a better path? It connected
directly to the Stemmons Freeway.
You are the new game player on here as Brown has taken a hiatus. The WC claimed
in 1964.that Main Street was better and that the two turns were needed, but they FAILED to support these claims.
Now, in 2018, you are trying to get me to disprove their claims when they NEVER supported them let alone proved them. It won't work. Elm Street was as wide as Main Street and connected directly to Stemmons Freeway, thus, it was the better option. Live with it.