Bravo! Well-written, well-argued!
I grew up in Dallas and our streetcars (NOT the current DART light-rail system or the McKinney Avenue Transit System tourist line) disappeared in the late 1950's for many of the same reasons.
The Dallas Railway & Terminal System DID have a modest fleet of PCC streetcars. They were sold to Boston's MTA and ran twenty more years, outlasting the buses that Dallas Railway & Terminal and the Dallas Transit System used to replace them.
Another factor that led to the demise of streetcar systems coast-to-coast is what I call the "Babbitt Factor." That is a combination of the belief that anything newer (and widely-hyped) is better than existing technology and the fear of many city fathers (Yes, a sexist term, but local governments were rather more often than not male-dominated fifty, sixty, seventy years ago) of seeming "old fashioned." I don't doubt for a minute that dozens of trolley systems were torn up because city mayors and councilmen chose to believe the BS of bus salesmen that their cities and towns would seem old-fashioned and behind the times if they continued to run "old-fashioned" trollies.
That sort of BS argument led to the end of Austin's last trolley line just before World War II.
National City Lines would never have been so successful at doing in trolley systems without the active collaboration of numerous city governments.