Aiwa is a Sony subsidiary, not Sanyo....
HD-DVD and BRD have more similarities than differences so making one format would not be that hard
Blue Laser wavelength
Advanced Sound and Video Codecs
Physical size
are both the same on BRD and HD-DVD, so a single format that can read all disks is far from impossible.....here are the differences, IIRC:
Numerical Aperture(BRD=0.85/HD-DVD=0.65)
Minimum Pit length(HD-DVD is 204nm and BRD is 160nm for Prodata disks[23.3GB/46.6GB] or 140nm for 25 and 50GB BRDs, or 138nm for 27 and 54GB BRDs)
Track Pitch (0.32 micron for BRD and 0.40 micron for HD-DVD)
Read Power (0.35mW for BRD and 0.50mW for HD-DVD)
Physical Data layer (0.1mm for BRD and 0.6mm for HD-DVD
Other differences include the fact BRD doesn't have to rotate as fast as HD-DVDs to reach the specified 36mb/sec data rate...in fact, a BRD rotating @ 10K RPM would be a 12X drive but an HD-DVD rotating at 10K RPM would only be a 9X drive....this is a by-product of the Numerical Apeture of each format and yet another performance advantage of Blu-ray...
They also have different software layers (BRD runs a java-based OS while HD-DVD doesnt) but for all these diffrences, a unified format is more a political challange than an engineering one.....this fact has been admitted by architechs of each format for a number of years...