True, Sony backed Betamax, which failed. Sony backed pre-recorded Mini Discs, which failed (don't believe me? Go into any record store, find an Album you like and try and buy it on Mini Disc). Sony is backing UMD Movies, which are apparently failing (
http://www.reghardware.co.uk/2006/05/03/npd_sony_psp_umd_future/), and Sony are backing Blu-Ray..