It is possible that digital dollar could pose a threat to Bitcoin's market share, especially if the digital dollar were widely adopted and used for a larger portion of financial transactions, not with like 15+million transactions per second. However, it is also possible that the two could coexist, with people using both for different purposes. Bitcoin has a strong network effect and a loyal user base, so it is not likely to disappear anytime... Ultimately, it is difficult to predict how the hell two will compete with each other, as it will depend on a variety of factors such as user adoption, the development of new technologies, and changes in economic and regulatory environments.