You... think that was a mistake? Blu-ray mainly won over HD-DVD because it was built into the PS3, same way the DVD player in the PS2 gained them loads of sales from people looking for a good DVD player as well as a gaming system.
Another thing to bear in mind is that Sony had a hand in Blu-ray's creation, and therefore stood to profit from its success. Making less money than the could have from a console has its disadvantages, but probably balanced out with the money the got from BR licensing (presumably they hold/share the patent and therefore get a little money from everyone who manufactures the drives).
EDIT: Oh, and I don't see them switching to holographic just yet; it's still a long way from mature, would be exorbitantly expensive to include at this time, there's still plenty of money to be made from BR, and as far as I can see from a quick look, they don't even have any involvement in the major holographic formats.