As of 2015, the platypus is not considered extinct. Instead the platypus is actually in "least concern" status by the International Union for Conservation of Nature, which implies that they were evaluated to have relatively stable populations.
In the past people hunted platypuses for their fur, which is what led to conservation efforts to create laws that protect the platypus populations in Australia. While the Platypus is not endangered, it is estimated that the platypus populations are on the decline. This is due in part to drought that have faced Australia, developments of dams, other irrigation projects, as well as increased pollution. Even with these increasingly unfavorable conditions, platypuses have been able to maintain the same population distribution in the areas they inhabit.