We are rapidly heading to a "Minority Report" world. In 15 years in new houses every wall will be a huge touchpad/monitor/screen. You'll be able to project/display any movie poster on your "wall" for zero cost. All printed/physical media - posters, books, records, etc. - will seem quaint.
Still, some people will want to collect and/or display physical posters, just like some people collect first editions of old books, even though you can download out-of-copyright books for free. But they'll only want the very very best old posters, not the junk from the last few years of movie posters.