do all feral dog populations end up looking and acting like dingos eventually?

Dingoes are wild dogs found in Australia and SE Asia from Papua New Guinea to Thailand.  There have long been debates about the relationships between domestic dogs, wolves and dingoes, but recent genetic analyses suggest that dingoes are a genetically isolated group of domestic dogs.

Consequently, dingoes are, essentially, feral dogs which have, in the case of Australia, been isolated and interbreeding for about 5,000 years.  Domestic dogs which become feral in Australia, often pig hunters' dogs which get lost, interbreed readily with dingoes, and there is concern that there are few if any populations of 'true' dingoes left that are not significantly interbred with domestic dogs.  So to your question - feral dogs do tend to group into packs with strong hierarchical structures, and which hunt cooperatively, as do dingoes.  But feral dogs are unlikely to become more dingo-like in appearance, as the distinctive breed characteristics of dingoes are the result of thousands of years of isolated breeding rather than their being wild or environmental factors.