Agreed, devs really need to start again with playable Demos, it used to be my soul reason for choosing games. I recall playing a time limited demo of Absolute Pinball for months and to keep it running all you had to do was either uninstall and reinstall or set your clock back 3 days.
If you go back to the early - mid 90's it was all about the demos every magazine had a demo disk on it, ID and Raven Soft used to give you the first 3 levels of their games as a demo (Doom, Hexen, Heretic) as far as piracy goes it's sad to say but it'll never stop (twin VCRs scart linked, recording the top40 off the radio, floppy drive Copy X, CD ROMs, DVD Roms, BRay Burners now it's all digital copying) it'll never end.