Sorry, but your comparison doesn't hold. Here's a quote from MusicDirect:
We at musicdirect love SACD. Compared to CDs, the music is simply more emotionally involving. The sound stage is wider and deeper, and instruments have a dimension not achievable in the standard CD format. Music lovers will be literally immersed in their stereo or multi-channel performance because of the extended bandwidth capability that DSD offers. The hybrid dual-layer Stereo or multichannel SACD also contains a high quality CD layer. Its backward compatibility makes sure you can enjoy your favorite recording anywhere. Because the CD layer is generally created by downsampling from the DSD master, its sonics are also much improved over the standard CD.
They, among other online vendors, sell a still evolving catalog of SACD titles. The Oppo is priced higher and serves two market places, both of which are willing to spend a few dollars on a suitable player. The market for a combo Blu-Ray/HD DVD player has only been shrinking and HD DVD player purchasers are not generally used to having to spend that much for a player.
Yes, you could potentially spend a bundle for a combo player and pick up the remaining HD DVD titles for fairly cheap. Or you could spend far fewer dollars on a BD only player and put the saved money into those same titles on BD. OR
you could spend especially little and pick up an HD DVD player on Ebay
! No point in targeting a niche if you can't make it pay off. Marketing is all about making the manufacturer's investment successful after careful qualification of viable target markets. HD DVD simply isn't!