Definitely agree the extra year or two makes a big difference. It’s been common in the past in Track for athletes to stay in school for five years and compete for four seasons (not in the Ivy League, of course). Adding a sixth year for those kids, plus watching the Ivy kids go on to compete for a fifth and sixth year, makes the developmental difference of that extra year or two pretty clear.
It’s tough for that first class moving through without extra Covid years, as they’ll never be the oldest. And it’s the top athletes that tend to stay.