Not all software. Linux is over 25 years old and shows no signs of abandonment. I think the odds are very good that it'll still be in use a century from now. Apache is almost as old, if you count its NCSA roots. Microsoft SQL Server is basically 1990s Sybase with a new GUI. Etc.

I think the odds are much higher that we'll see the end of significant advancement in computing power than the odds that we'll see Linux pass into memory. In Vernor Vinge's marvelous novel A Deepness in the Sky, programmer-archeologists dig through millennia of software on a 5000 year old spaceship, but it's still running Unix underneath, because no one ever came up with anything better.