The Fed can easily replicate the benefits of cryptocurrency in seconds. They simply need to come out and say "We will only print X number of dollars, every Y number of months".

There you go. All the benefits of Bitcoin replicated in the USD, which is a far more widespread and versatile currency?

So why doesn't the Fed do it? Because it really is a terrible idea. It's like pegging your currency to gold, which was a terrible idea (although good for its time) and the delay in moving away from it probably cost tons of money and lives.