So why has Mazda sold more cars in NA, where presumably there is more snow through out the year than the US?
Please tell us you're kidding.
The last time I checked, North America included Canada, United States and Mxico.
In what universe would it be possible for sales figures from country X to be greater than sales from countries X, Y and Z added together?
I didn't think the CX-5 was that good in snow, no lock and wide tyres?
You have been misinformed.
Having recently used a AWD CX-5 as primary transport to ski over 50 different days at the snowiest ski area in the world, Mt. Baker, WA (yes, they have the world record for the most snow), I will attest that the CX-5 handles winter storms, unplowed drifting snow, packed snow, slush, and unsanded icy roads like child's play. Too bad I was typically held up by large American SUV's that had trouble getting out of their own way as soon as the road became the least bit slippery. Because when I had clear road ahead of me I could haul ass and the CX-5 is the most capable vehicle I've ever driven on Mountain pass highways under winter conditions. This list includes a long list of AWD Subaru's, Volvo's, VW's, and American and Japanese 4x4's. The Mazda has them all beat, some by a very wide margin.
I was concerned Mazda might not know the finer subtleties of tuning their traction and stability control systems for ice and other very low traction surfaces but this was a misplaced concern - the systems are very capable of handling even the most treacherous conditions.
BTW, the last thing one want to do when driving on slippery snowy or icy roads is to deploy a locking differential - Mazda's AWD is many times superior in slippery winter conditions than any vehicle with a differential lock. As an ex-off road enthusiast I can say a locking differential is of no use (dangerous even) under such conditions.