This is hard to answer, we simply don't have a lot of data on their distribution and it is only in the last few years that they have received attention. Most species that were once known only from a single location were subsequently found elsewhere and some of these species turned out to be much more widespread than what it initially looked like. Having said that, there are a number of species that still have not been found at more than one location despite an increasing number of people looking for them, among them are Maratus bubo, Maratus trigonus, Maratus personatus, Maratus unicup, Maratus electricus, Maratus tortus, Maratus aurantius, Maratus lentus.
There is the possibility that some may indeed be restricted to a small area and if that is the case they would be quite vulnerable to any changes in their environment, including fire. Maratus sarahae is only known from the two highest peaks of the Stirling Ranges, where climate and vegetation are unlike anywhere else in Western Australia. It is not that hard to imagine scenarios under which these populations could be wiped out. In 2018 a large fire burnt at or near the area where Maratus sarahae lives. The Australian continent has been subject to significant in the last two hundred years, in particular in the southwest and southeast of the continent where peacock spiders are particularly diverse. I suspect that many species have already been wiped out and what we are seeing now may be the tip of a large iceberg.
Compared to fires and other forms of habitat destruction the activities of photographers and collectors are negligible, but these too are likely to have some impact. At the end of spring right through summer female peacock spiders spin an egg sac for themselves and their brood and they remain inside the egg sac for at least one months. The egg sacs are woven between dry leaves or other debris. It would be impossible IMO to avoid stepping on them when walking around looking for the colourful males.