Appreciation in fix n upper

[Aswin Elam]

Hi. I am new to real estate. Trying to learn from scratch. I have watched many podcast and webinars. When we buy single family homes around 150 k and we try to get fix n upper, we will end up buying older houses that’s 30 to 40 yrs older.  And everyone thinks of keeping it for ever (hypothetically) won’t the old houses get much older and doesn’t the prices go down instead of higher.  Say we keep it for 20 yrs, won’t the house be much much older.  
please help me understand, thank you.