……….well, I’ve been involved full time as a broker and developer since 1971 and I have not heard what you are quoting.
More info would be needed to properly answer the question you raise e.g. 1. Which direction from downtown? 2. Square feet?
3. Address is important. Meaning the neighborhood the house is in. 4. How old is the house?
With those answers, I could tell you whether or not what you heard is close or not.
Like you said, thousands are moving out of Austin, far more than would move there. It is a city that is losing population Look at Detroit, Cleveland and Buffalo. People move out and property prices tumble.