It wouldn't be the first time
While I hope you're right about no hiatus, there has been one between every new manned system since Mercury.
Mercury manned flights: 1961-63
Gemini manned flights: 1965-66
Apollo flights: (including Skylab & Apollo-Soyuz): 1968-1975
Shuttle flights: 1981 to present (with two big stoppages due to accidents)
