has it halved?

Yes it has.
why hasn't the price increased?
Everybody knew when the reward would halve...so they were all mining and buying it like crazy before it happened (inflating the price.) It's the same routine every time a currency halves - price typically peaks right before it happens and then actually drops. Network speed (and therefore, difficulty) drops 50%+ as well so it remains just as profitable to mine as it was shortly before the reward reduction. This goes against conventional wisdom...but makes sense when you think about it. The good news is that you don't always have to be an early adopter to turn a profit...and the bonus rewards are there early to lure in miners and reward them for taking a chance early on an unproven currency.
People think they'll make a killing with the bonus rewards but it ends up being a wash usually. The bonus rewards are never as profitable as they seem. Look at PHS right now - with the double rewards, difficulty was over 4 at one point toward the end. After being halved, the difficulty is dipping below 1 now. I'm actually mining nearly twice as much PHS as I was before the reward halved. Look at MegaCoin - the reward halved and the difficulty dropped to 1/4 of where it was before. End result? I'm mining MEC twice as fast as I was before the reward halved (reward is half, but Im brining in 4 times as many blocks.)
The majority of people tend to think the same way...so I prefer to sit back and see how it plays out. Haven't really missed out yet.
None of those coins you mentioned will halve their subsidy to 0.01 per block. Just some food for thought...
That fact doesn't change the math. If the hash power is cut in half, the difficulty is also cut in half. If both the reward and difficulty are halved, the currency can be effectively mined at the exact same pace. Sure there is less of it being created, but you aren't going to feel the impact of that right away.
Of course the value/price should go up eventually -- it should go up considerably. I'm just saying people always expect the price to skyrocket immediately after a reward halves...but since everybody is buying/mining like mad before it happens the price is already inflated. We aren't talking about a surprise event here -- everybody knew it was coming.
I love CGB and the rarity is definitely being underestimated. I don't care what the price is at right now, because I'd never even consider selling at this point. I just keep mining and pushing forward.