it would depend on the government and the situation. I suspect most don't realize this is possible. a small government can generate immediate demand for their currency doing this.
The original e-cash paper is from 1983. Governments absolutely know this is possible.
It's just much "too private" to get any political traction. At the very least, I suspect an acceptable modern alternative would either have caps on what can be sent/received completely anonymously (e.g. per recipient and timespan) or want non-anonymous recipients (to allow for VAT/sales tax accounting etc.)
