Quitting at 22 seems strange now but was not in earlier times.
Arnold Strode Jackson of the UK won the Olympic 1500 gold medal in 1912 when 21 and retired.
John Woodruff of the US won the Olympic 800 gold in 1936 when 21, ran another 3 years and retired
Wes Santee, 3-time US champion 1500m/mile, AR holder in the mile and WR holder in the 1500m, and an Olympian, retired at 22 after getting grief on expense reimbursement from the AAU
Bruce Kidd of Canada , an Olympian and 2-time US XC champion, retired at 21, Injuries I think
I used "retired" loosely, as each of the above may not have officially announced a retirement at that time, and may even have run a few more races (like Elliott), but I believe they stopped competing running at the international level at the ages above. People can correct me if I am wrong on any of the ages.