Hi,
Because the waitlist data is not stored in the product table but in the "waitlist" table and the HikaShop import/export are not handling that table.
And I don't think that's a good idea to add the waitlist data in the product export ; I think it's better to have just an export of the waitlist. I will add a request in the TODO list.
You can access to the waitlist data in the HikaShop backend, under "Customer > Waitlist".
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.