It’s true, you can’t take it with you. When you die, you will be forever separated from your stuff. That’s why Jesus said not to store up treasure on earth; it’s not that earthly wealth is bad, it’s that it’s temporary. Rather, he said to lay up treasure in heaven. Why? Because it’s forever. So Jesus’ point in Matthew 6:19-21 is not that we shouldn’t store up treasure, but that we should change the location of it.
It’s interesting that Jesus doesn’t make an emotional appeal, but a logical one: Don’t spend all your money on something that won’t last when you can invest in the Kingdom of God, which is forever.