It looks HTC is trying to get at least some HTC One sales out of the door before the Galaxy S4 is unveiled on March 14th, as they are going to ship the One on the same day in UK, at least with one retailer (Expansys). HTC was able to release the HTC One X last year about 2 months before the Galaxy S3 was even announced. At least that helped them get a boost in sales when they first started selling it. But this year they might not be so lucky.
While they are going to ship the HTC One about exactly one year after the One X, it looks like Samsung is going to announce and release their own flagship earlier this year, perhaps to eliminate any threat from HTC, but also to ensure a several months window between the Galaxy S4 and the next iPhone, which is also rumored to launch a little earlier than last year.
HTC is not doing very well at all so far, and the situation is only looking worse and worse for them. The Galaxy S4 being announced months earlier than it should've been could put HTC on an even faster decline. This is why shipping even days earlier could mean saving someone's job over at HTC.
In the same time, while Samsung is powerful (in marketing especially), it doesn't necessarily mean that everyone will get a Galaxy S4 and will completely ignore the HTC One. If anything this could turn out in HTC's favor, if people keep putting HTC one next to the Galaxy S4 in their conversations, or when they're recommending phones to their friends. Or I could easily see the store representatives giving people the choice between Galaxy S4 and HTC One, both brand new. Even if Galaxy S4 would be a bit faster, perhaps people will prefer the One's design or build quality, over Samsung's inevitably plastic-made casing.
HTC could even run away with this in their ads, and present the One as some sort of "antithesis" of the Galaxy S4. HTC probably doesn't have a lot of money to use for advertising now, which is why it's that much more important to be smart about it, and make very effective ads that sell their product. HTC One might be HTC's last chance, especially if they aren't even considering making a Nexus phone or Nexus-like devices.