That starter system didn't serve any big destinations outside of downtown. It failed to run up to the Stockyards, and it failed to run down Magnolia.
The thinking at the time amongst a lot of Near Southside powers-that-be was that running the first line down South Main (which would've been the first part of the system constructed) would prompt the Magnolia expansion on a faster timescale. There were talks about ways to fund the Magnolia expansion as rapidly as possible using Southside local dollars, following the go-ahead to start building South Main.
It's been years and I don't recall where things were left off, but for obvious reasons, these plans were shelved when the main project was canned.