Absolutely yes! Digital dollar is not just a mere possibility, it's an imminent future!
Majority of the developed nations will digitize their fiat system sooner or later because it has some major benefits if seen from the perspective of a government. It will offer them the power of supreme vigilance.
Supreme vigilance: if the entire fiat system is channelized through a digital platform, enforcement agencies will have complete visibility on what's happening on the economic front. Money laundering will be caught immediately. The chances of tax evasion incidents will be reduced to zero annd most importantly, financial crimes will be easier to catch and prove.
So not just US, you can expect all developed nation to issue their own digital currencies in future.
I hope so. After all, the US has been known to be quite restrictive when it comes to crypto and Blockchain technology. Even the President of the US have expressed his negative comments about digital currencies (mostly related to Libra). If other countries take the lead in adopting digital currencies of their own, then I see no other way for the US to survive with USD as the world's #1 reserve currency. I guess that once the US sees other countries launching their own digital currencies, it'll be forced to launch a digital version of the US Dollar within the mainstream world.
I have to agree that with Blockchain-based digital money, it becomes much easier for governments to be able to track malicious actors on-chain. Money laundering and other criminal activities will be reduced to a minimum due to the transparency of the underlying Blockchain ledger. Government-sensitive transactions, can be easily obfuscated via the use of privacy technologies like ZK-SNARKS or even Mimblewimble. Considering that our world is becoming largely dependent on the Internet, and electronic payments (like credit cards, etc.), it's likely that every country in the world will have their own digital currency within the not-so-distant future.
Nonetheless, time will tell us if a "Digital Dollar" will become a reality or not. Everything will depend on the US government itself in order to eliminate physical cash (USD) for good. With the US' collaboration, we could experience a cashless society sooner than we've thought. I believe that slowly but surely the US and other countries will start launching digital currencies of their own until physical cash is wiped out of existence once and for all. Just my thoughts