I have seen it with my eyes in the last 6 months and it seems to be a model that never stops working. I'll specifically name Adobe, HP and Oracle as offenders. There is only 1 sales model I'll accept. A 30-day limited developer license to install/access and tinker with your product. Maybe companies exist that are "doing it right" but the old way is still alive and kicking and raking in millions.
It's not a matter of building out your entire project, it's just to get a feel for the quality and decide if it's complete bullshit. If you think 30 days isn't enough time, then a vendor demo is worth less than zero.
EDIT: Exhibit A-Z is the current $240M lawsuit by the State of Oregon v Oracle: http://www.bizjournals.com/portland/blog/health-care-inc/201...