When the nature of the problem is such that rational customer behavior leads to one player taking all, the market deteriorates, and customers lose the benefits of competition.
This is a problem that the anti-monopoly laws exist to solve.
Another body of law prevents the federal government from seizing all the power, and to keep different branches on power competing without mergers and acquisitions of each other.
An anarchist / libertarian approach would work if minting your own interoperable coin was possible and reasonable. With gold coins, it is (was) technically trivial. Digital currency has still to solve this.
Not only that, but all these self-cryptos would be backed by the word of the person, and people lie, so you could potentially just end up with a whole bunch of crypto coins worth nothing in the end.
Gold has some intrinsic value (you can make stuff out of it at least). Same for makeshift currencies like the Tide detergent.
US dollars are backed by US industrial and military power.
Random crypto tokens have about as much value as paper money: they are relatively hard to produce, but not very much so. They need to be backed by a power / reputation of some kind, or a directly consumable resource of some kind, to be widely usable.
If the USD has $1TT stolen or an anti-counterfeit measure is bypassed, the US government could step in and support use of the dollar with some guarantee or security advancement like better counterfeiting protections or freezing stolen assets then (as bad as it is often seen) printing replacement bills or something. Some of this is already ongoing with the Mint developing anti-counterfeit measures for each new bill released.
Crypto can't do that, it's just a volatile stock like commodity with no underwritten assets or real world backing. There's no centralized backer that can prop it up in crisis. That's risky.
Google is far less likely to ever let you tell them what they can or can't do, even as a regulator. The government is you, fundamentally, while Google is not.