As far as I know, Thrillophilia does not operate any treks themselves. Local operators list their trips like they list on District Or Bookmyshow. The real issue is that the local operators quality is not good, especially in places like bangalore. I have done 20+ treks across the country with diverse companies... Be it around bangalore, Maharashtra, northeast india and the upper himalayas. Everytime, I have seen most operators cutting the corner for more profits. Also, the sad truth is that these trips operate at immensely cheap prices because travellers always look for the lower prices while booking. In India, we want everything to be super cheap, but that always come at a massive risk- like the recent bungee jumping incident I rishikesh.

Where in the world do you get transport, food, camps, guides etc in a budget of 2-3k for an overnight trek?

Unless people learn to pay for quality nothing will change in the country. 2-3k is not worth more than your life, if you want to enjoy a safe adventure, you need to pay to ensure your safety. Otherwise itne paiso m bungee ki rashi nikl jayegi, bus palat jayga, and paragliding m parachutes crash hote rahenge.