I disagree with this notion.
In my post about team development I give some examples of how I approach the building of a continually winning team, with striving to be in the playoffs each year.
I agree alot of players don't think with long-term planning, and thus are unable to combine building with winning.
Look at the actual Atlanta Braves...they win as they build.
You need to constantly draft well, both in the rookie and free agent drafts to stock your roster.
Sometimes you have to draft the prospect in the free agent pool (for future use) ahead of the solid veteran that you could use next year. That is the key to building long-term winning teams.
I see alot of teams that display the bipolar pattern of winning one year, losing big time the next season, then winning again. They have no continuity/long-range planning for a consistent winner.