I'll just add, as someone who works on packaging of guile in pkgsrc, that we have had to have multiple versions for a long time. There is software useful enough for people to want, with various requirements. Currently we have
1.8 2.0 2.2 3.0 If there were more concern about compatibility -- all 2.0 programs will compile an work with 3.0 -- then we would not need to keep the old versions.
