When you have a display that can handle the frame rate necessary to alternate the picture anyway... what's the cost?
- The weird proprietary connector, that goes to the weird proprietary array of infra-red emitters that needs to send the signal to sync the eyes.
- The integrated IR emitter in the TV that emits the sync signal to the 3D googles.
or, for TV that don't use active glasses
- A weird structure in the pannel that makes sure that every pixels emits light in a different polarity than it's neighbours
(either alternating horizontaly in scanlines, or vertically in column, or in a checkered pattern... whatever, as long a "left image" and "right image" pixels emits different light polarities that will subsequently get filtered by the passive 3D glasses)
(BONUS point : this setup gives dual-viewer capabilities (viewer A and B get to watch 2 different channels thanks to the glasses) which might be popular in some market with cramped living rooms ? Japan ?)
or, for display that do not use glasses at all (e.g.: Nintendo 3DS)
- an even more complex lenticular filter that makes sure that 2 different images are sent in 2 different directions (a little bit like a privacy screen, but viewable from 2 different angles, each showing only half of the horizontal resolution).
and starting from New 3DS, an even more elaborate viewer's face tracking technology to make sure that each of the view eyes get the correct image at the correct perspective.
So, in short : only the most clusmy 3D glasses are those that require the less hardware.
Out of them, only the first variant (proprietary connector) is the easiest to remove (say that the 3D pulse can be sent of the almost-never-used analog headphones jack),
and will still require a clunky setup (an IR emitter bar and active glasses) that will be quite off putting.
Meaning that even less people are likely to try the 3D, except to the 2 geeks at the back over there.