1) Who is it that you think works for those software houses? Someone still has to write all that off-the-shelf software. As computers improve, and new ways of using them appear, and new paradigms are developed for HCI, then that software will continue to be developed and reworked to take advantage of those.
There are things that can be done with software right now, that couldn't have been done 5 years ago. In 5 years' time, things will be possible that aren't right new. New scientific innovations, new technology, new business ideas will all arise, and will all require new software.
There's more the the software industry than computer games and MS Office-wannabes.
2) You seem to have no idea of the depth and breadth of things software is written for. In my time, I've developed software for analyzing molecular similarity, modelling oilfields, automatic management of PC networks, health monitoring for jet engines, mission planning for military operations, DNA sequencing, and more.
And I've interviewed for companies working in dozens more different areas. If different job opportunities had opened up, I'd be giving you a completely different list.
So, tell me - exactly which off-the-shelf software packages (produced by software houses who, apparently, don't need to employ programmers) should those companies have bought, instead of recruiting developers to write the software they needed?