FWIW, in my time working around sports games I can't think of a single example where someone discussed not implementing a feature to save it for the next year. I don't believe this is a real practice and it's one of those things I'd hear people say that I always found kind of funny.
When you look at whether or not individual titles are successful there are a lot of variables in addition to quality and what features are on the back of pack. Other games shipping in the same window, things that would affect how you put together your marketing budget/plan, etc.
The thing is, the majority of players don't purchase these games every single year no matter what. There are some years where a game goes above and beyond and captures more audience than usual. When that happens it's true it can be tough to get people to go back to the well the following year. But it tends to be tough regardless, so holding stuff back isn't in anyone's best interest.
I'm not disputing the anecdote BTW. Just not sure I buy it as a common marketing strategy for sports games.