probably because most of users either stick to the older xz or just skipped the xzs
well where I live the XZ/XZ Premium are the only officially available flagships , no xzs no xz1
also because of that I found deals of xz premium for almost same price as xzs or even lower !
but just be patient I remember back last year or so first when Z5 was out the first few months it's forum section nearly empty.. so yeah just wait and see