It's amazing that they don't, really. They come from Australia and New Zealand. It's 14 or 15 hours by plane. I've never used that resource myself, but I did help a neighbour this spring. Those bees look great. There is a downside to them in that they're coming from an area that's just going into winter, so they're largely old bees.
A traditional area for importation of packages has been California. When they come in April, they're young bees that have hatched within the last two or three weeks as they've come off the almond crop. The hives are really stimulated in February with the almond crop and the hives are burgeoning in April.
When they come from the South Pacific, they've produced a honey crop and they're getting ready to go into winter. There's a bit of an issue there, but it's not huge. The biggest issue is the genetics of the queen. They are from a South Pacific climate and environment that does not have much in common with North America.