I'll buy 48 hours on a WIL check, but anything past that requires knowledge of tricks (like, say, electrolyzing your water supply WHILE you're wearing the suit without electrocuting yourself).
In this specific case...
What does the Survival skill do?
It allows you to survive.
There are three usual criteria....
Find shelter. This would mostly be find somewhere covered, out of the elements, dry, secure and away from animals. There'd be various techniques to improve a shelter, or assist in finding one, but the most environment specific feature would probably be in constructing a shelter. Building an igloo would require different techniques than building a treehouse or using bamboo and leaves to create a tent. Different environments also have different dangers...floods aren't likely in arctic areas, but blizzards are and building off the floor to escape insects and snakes is often more a concern in jungle regions.
Finding water and recognising that is safe, or treating it to make it so, would also be ubiquitous. Building a solar still, construction of a filter, the desirability of boiling and avoiding areas where water and life don't mix.
While there are environmental concerns with water and shelter, the most applicable justification for specialisation in the survival skill would be finding food. There would be a huge amount of variety between environments as looking for food in a jungle is very different from a desert is very different from a tundra, etc
Two parts would be locating food and making sure it is safe to eat.
Overall....it strikes me that specialisation is both justified - someone trained to survive in a desert environment would have an advantage - and yet there is a huge degree of overlap in the skillsets. Even with food, basic rules for testing foods for safety could be applied to most regardless of specific environment and, even on Earth, the Sahara and Gobi are very different, as are the Arctic and Antarctic.
Specialisation feels right but is arguably unnecessary....unless you also assume that it affects the ability of the player to survive exposure. Survival (vacuum) trains you how to increase survival when exposed to vacuum whereas Survival (Jungle) teaches you how to survive the heat and humidity of a Jungle, Survival (Desert) teaches you to move at night and water conservation tricks, etc
The skill represents more than knowledge, but your ability to tolerate the conditions as well as the general tricks to ensure water is clean and food is safe.