Because you need a screen that will reflect the light back in a polarized fashion. In film terms, you're talking about a screen with silver crystals in it for reflectivity. But those screens are enormously fragile - which is part of why 3-D keeps flopping over in theaters - if one person throws their drink at the screen, or even touches it, the screen is wrecked for good and needs to be replaced.
That's not technology suitable for home usage. Which is why home systems have always been based on field sequential systems of 3-D.