Passive 3D vs Active 3D

[brdmaverick]

Newbie here, so please bare with me. I'm really wanting to get a 3D but realize I have much to learn. In going through these forums it appears that the biggest differences between ACTIVE and PASSIVE are.......

ACTIVE
FULL HD but...
expensive glasses
ghosting
headaches
flicker

PASSIVE
Cheap Glasses, no ghosting, but......
lower resolution 540P

But then I read how 4K TV can do PASSIVE in FULL HD. Shouldn't this be the end of the conversation that this is the perfect solution (well, except for the money that needs to be shelled out).

I'm doubting myself b/c why aren't all 4K TVs passive if this is in fact the best solution?


Also, when we say that 4K can do full HD that is to say that if I have a 3d Blu ray player and a 3D Blu ray movie, I should be able to watch it in FULL HD right?

it's not like it has to be a 4K 3d movie, right (do those exist)?