I actually think that your logic is one of the reasons that US investors, to their detriment, will be later to the game than many others around the world. If you live in Argentina, Venezuela, South Africa, Iran, etc... then monetary debasement is not a philosophical issue, and you are probably certainly willing to take small positions in any assets that potentially have the ability to hedge that risk.
On this point, there is nothing that says you need to buy 1 bitcoin at a minimum. You can buy very tiny fractions worth of one bitcoin. And I think while that's already been happening, the introduction of bitcoin purchases on highly mainstream financial companies like Paypal and Square will only make this more common place. So I would agree that if a young person only had 15,400 of dsicretionary spending this year, they'd be better off learning to code than they would be buying a bitcoin. But they might be best off spending 15,000 learning to code and buying 400 in bitcoin.