Marketing / Brand Recognition is important for the masses
Us tech geeks can look at the specs and price of a phone and use that information to make a decision on the product. But half the reason why Apple / Samsung and Sony hold big swathes of the market is obviously the swanky marketing, but the brand recognition too.
I can guarantee that neither my girlfriend or any of her friends will have even heard of Huawei, and if the Honor 7 isn't available somewhere like CPW or other carrier's stores, then it's not going to get much traction.
As a side note, I did have a Huawei Ascend G300 (and still do as a backup phone) which worked perfectly well when it was my main phone. It started out iwth Gingerbread and did get an upgrade to ICS.
However, in line with other posters, I'm unconvinced about the likeliness of security updates and support. My concern would be, if you attempt to buy this phone directly from Huawei and their website isn't setup to cope with even buying a phone, how would it cope with having to send a phone back, owing to a fault?