My grandfather died in 1965. His house was worth $8.5k, per when we sold it.
That house is now worth $450k in 2021 per Zillow
2021- 1965 = 56 years
56th root of [$450/$8.5] = 1.073 -> = 7.3% return compounded annually over 56 years
My grandfather built that house with cash, so that is realistic.
But if the had a 20% down 3% interest 30 year loan, his return would have been more like 20%.