Well, their arguments[1] are quite compelling in general, rest of the software[2][3] seems to be highly specialized and specific, I'm guessing there is a lot of maintenance that has to be done still.

- [1] http://www.symbolics-dks.com/Genera-why-1.htm

- [2] http://www.symbolics-dks.com/Macsyma-1.htm (general purpose symbolic-numerical-graphical mathematics software product)

- [3] http://www.symbolics-dks.com/PDease-1.htm (general purpose software that uses Finite Element Analysis to obtain numerical solutions to a large class of partial differential equations)

I believe those instructions do not work anymore. There's a project on github that will build an appropriately old ubuntu vm that runs open genera pretty well provided you have the source. You can also find the source tarball without too much hassle on some torrent sites.