buying bitcoin / cryptocurrency is basically the same as buying land, but if you buy land you have to trust a third party that is the country that houses the land.
You can't "just do" whatever someone is doing for a number of reasons. One, the time before is different with the time that we have now. Before, you can buy tons of land with just a little bit of cash. Elders used to say that they used to be able to buy lands in exchange of a pig or a cow and those doesn't cost that much. So pretty much what happened was that his grandfather was able to buy tons of lands and now that the world is more populated that it ever is, those lands are now cost a lot more. Second, just because you bought a property or a land, doesn't mean the price of it is going to grow. Sometimes properties like land is just a good way to store your money as they don't usually devaluate. Third, everyone is already in this business and if you're going to buy a land, you're essentially just giving someone his/her long-awaited profit.