MINOS, CPLEX, XpressMP, OSL, KORBX, GAMS, AMPL, and many other optimisation packages came out of that period. Those packages were not free software or open-source software, but they were available to researchers at universities in the First World. (It seems unfair to expect software from 1978 to be free software or open-source software as we understand it today given that the FSF dates to 1985 and the term "open-source" to the late 1990s. Also bear in mind that personal computing was in its own initial boom in the 1980s.)
Papadimitrou and Steiglitz's book (published 1982; I have the 1998 Dover edition) has an exercise (Chapter 15, exercise 19) in which you are to read a short 1979 New York Times article about the ellipsoid algorithm and "[d]etermine, where possible, whether each statement is (a) true, (b) false, (c) misleading, [or] (d) equivalent to a well-known conjecture, the solution of which was probably not known to [the article's author]."
There's a longer article written by the same author 20 days earlier, too, and that one has more unfounded speculation about applications of LP: https://www.nytimes.com/1979/11/07/archives/a-soviet-discove...
Karmarkar's 1984 interior-point method begat similar excitement, leading to a few thousand papers through the late 1990s, and a trickle still today, on interior-point algorithms of varying correctness, generality and efficiency.
The technology that came out of that hype cycle is phenomenally capable and usable, and it's subsequently been improved even further.