Because it's prelaunch trading. There's no actual blockchain, i.e., no actual Qtum coins being traded. The only exchanges that can offer prelaunch trading are the five exchanges that participated in hosting Qtum's ICO.

You could make the argument that Bter and Allcoin are unpopular, but Yunbi seems to have decent volume (Qtum had >$30MM USD/24 hr volume just the other day on this exchange).

Is it possible that the price is inflated? Maybe. I doubt it, however. It's unarguably worth more than ETC because it is ETC w/ PoS 3.0, UTXO model-based, and a more ambitious dev. team. Admittedly, the circulating volume of ETC is 92,000,000 compared with Qtum's total volume of 100 million.

LTC? Well Qtum has adopted Segwit as well. Major difference then lies in PoS 3.0 vs PoW. Perhaps is the reason why the current market cap between LTC and Qtum isn't that far apart, and likely will be higher for Qtum at launch given public support seeming to favor PoS over PoW, at least certainly in the Ethereum community. Then there's smart contracts/Dapps, which LTC currently lacks. This combined with the lack of dev. team for LTC, albeit a single dev. was recently hired.

Qtum is Chinese Ethereum 2.0 with a seemingly faster, more innovative dev. team. While it's certainly possible for price manipulation, I highly doubt that is what's going on. I think people are coming to the realization that Qtum has the potential to be a real contender with Ethereum for blockchain technology, and we are still very early in the game.

If Qtum, or more specifically the Enterprise Qtum Alliance, is able to gather support from big companies, there will no doubt be a trend like that seen with the Ethereum Enterprise Alliance Announcements (a jump from ~$12-->~$50, then from ~$90-->~$230). I think this is also being factored into the price, given the collaboration with PwC.