Probably the best cycling analogy for a major champion retiring early and being done with the sport outright would be Miguel Indurain. He was only 32 years and 2 months old at the time, and for all the attention on his 11th place in the Tour that year, he still won the Dauphiné, the Olympic TT, and three other short stage races. Obviously a lot of the money saved via Indurain's retirement helped them get Olano, de las Cuevas and Zülle in the next couple of years, but they still had José María Jiménez, Ángel Casero, Santi Blanco, Orlando Rodrigues on the books at the time and would then add Unai Osa (plus his brother from Euskaltel) and Paco Mancebo from the espoir ranks, many of whom may have benefited from the veteran leadership of an Indurain.
Paolo Bettini, also, retired at 34 and stayed gone (despite the Italian taxman being on his case, which was a large part of why Davide Rebellin initially came back into his 40s), winning two Vuelta stages and finishing 9th in Lombardia as his final race. Certainly Il Grillo could have kept on racing at a high level for at least another couple of years.
It is worth noting that both of them had had a falling out with their teams at the time, though - Indurain's relationship with Echavarrí souring over an abortive Hour Record attempt in 1995 and severing over a 1996 Vuelta that Miguelón didn't want to be at, and Bettini being upset at Lefévère perceivedly low-balling him on a contract offer due to his age and signing Stefan Schumacher openly stating in public that he was to serve as a replacement for Bettini while they were still, as Bettini tells it (so not exactly a neutral source), ostensibly in contract negotiations with the Italian.