Is a crappy situation but patents don't enable the patent holder to make a product, after all you can make the product without claiming a patent. Instead they stop people who are not the patent holder from making that product.
So if we put on our tinfoil hats its likely that some "just in case" patents are really just stopping their competition from heading in that direction.
A great example, immersion held a patent and blocked the competition.
However if Sony (or anyone else) had developed and released a product (or even published a design) using the same technical implementation before 1996 then that would have established prior art and no one would be able to patent it.