Out of curiosity I decided to find a dealer listing the 125 and see what the list price was (because Husky doesn't have it listed at least not on the UK site). The first 2 I found didn't have listings at all, but Freestyle in East Sussex had one and it's listed for a whopping 350GBP less than the 401. This lead me to the answer to the question of why this bike exists and why it's in the markets that it's in. The 401 was intended to be a powerful bike that would fit within the UK's A2 license specification (<35kW of power, the 401 has 32kW). This license requires 2 years of motorcycle experience on an A1 bike to obtain and thus the 401 is not the starter bike in the UK that it is in the US. The A1 license requires no prior experience to obtain, but restricts motorcyclists to bikes with up to 11kW and 125cc. The Svartpilen 125 fits perfectly into that category.
So taking price and market factors into consideration it makes perfect sense that this bike would release in European markets (especially ones with similar licensing schemes) and not the US. Licensing in Canada looks like an absolute mess so I'm not even going to try. This all gives me a renewed appreciation for the simplicity of the American system where I can complete a 2 day MSF course and be free to plow a Ninja H2 into the nearest gorge. U-S-A! U-S-A! U-S-A!