Heavy Duty Phones

I would just like to know why Vodacom has such a limited amount of heavy duty smart phones available. I am specifically looking for a semi waterproof feature. The only viable option is the Sony Z3, which is a 2014 phone. I don't understand why phones like the Samsung S6 active is not available here. Africa is known for its hostile environment, why is it that I cant find a phone that will be able to withstand this environment? I understand that not all people require this from a smartphone but surely there must be more people that don't spend their working days in an air conditioned office? I cant ask this question to the sales consultants as they just sell what they are given to sell. I do not revel in complaining but I would like to know if there is a phone coming to South Africa that can cater for this environment. Your kindest consideration at your earliest convenience will be greatly appreciated. Regards, Marius