Why cant Blu-Ray and HD-DVD formats be combined into one HD-Blu Ray format?

Both Blu-Ray and HD-DVD use Blue lasers (the legend that HD DVD uses red laser is incorrect - check the official HD DVD site)

Also, both HD DVD and Blu ray can use the SAME compression algorithms (MPEG-2, H.264 or Microsoft's WMV).

However, there are differences in disc format, disc navigation, etc.

It costs extra $$ to combine the technologies, since one will have to pay royalties to both camps! yeah, and why can't Mac and PC, or VHS and Beta, or English and Spanish, or Satellite and Cable. Get it? HD-DVD is a Red Laser based media, just like current DVD's, meaning they are cheaper and easier to produce.

Blu-Ray is a Lavender (blue) laser with a shorter wavelength, and smaller impact area on the disc. This means more storage per square centimeter, but also significant extra costs involved in producing and distributing those discs.

So either way since both systems have incompatible lasers, you need to have 2 laser systems in any player designed to play them back (although it is possible for blu-ray lasers to read HD-DVD's but not vice versa). So there is an inherent problem in combining the two standards. You can of course get a dual format player for more than twice the cost of 2 individual players though (and not get the full benefits from both formats such as the interactive layer on HD-DVD's). The gentleman above is correct at some level, it's sort of like saying "why can't VHS and DVD's be combined into one standard?" They just cannot be that way!