DirectX 9 is pretty much a requirement for
most games these days. Just consider the fact that it runs at all a blessing

The engine itself probably isn't going to change to lock you out, however (I doubt they'd do that kind of major overhaul at this point in the games development cycle). The devs *might* place some kind of hardware protection on it (e. g. Oblivion actually checks to see if you have hardware T&L, and crashes if you don't.), but that kind of thing can generally be gotten around (Supreme Commander will throw a warning if you're below spec, but will let you bypass it with a command line argument).
To quote the
Pre Order FAQ on the subject of hardware requirements:
" The minimum system requirements for Beta 2 are the following:
- Windows XP SP2 / Vista
- 1.8 GHz Processor
- 512 MB RAM (1 GB RAM for Vista)
- 128 MB 3D DirectX 9 Video Card
- DirectX 9.0c
Final system requirements have not yet been determined."
So, ATM, you're supposed to need a DirectX9 video card. Just consider yourself lucky to be running without one