But do not feel too secured if you have lots of bitcoins. We do not know what will happen in the span of 20 years. I have faith in bitcoins that its price will still be on the top compare to other cryptocurrency, but we cannot tell. What if something happens, what if there is no more power supply, what if for some reason government find reason to ban the bitcoins. Instead of bitcoins, you may want to buy gold and silver.
Some governments have "banned" bitcoins but lets be honest there is no way to stop a community of strong individuals by just saying stop, the only way they could stops us is if they really wanted us to stop cut the power, but they would never do that because BAM their GDP sinks in the dirt, hope this information helped you out man but btc in 20 years id say $250,000 worth AT least.