I think when you look at the past decade or two of World Series winners, the most common path is developing prospects simultaneous to trying to compete at the MLB level (with varying levels of success). Teams like the Yankees, Giants, Cardinals all developed a lot of homegrown prospects, but they either did it while they were winning or during periods of downtime that happened despite their best efforts. At their worst, they resemble the 2013 Cubs. The whole "first we amass a pile of prospects, then we try to win, then we do win" paradigm has mostly been taken up by small-market teams that have had tepid at best results. The Brewers got their window, but it wasn't much of one and will end up being surrounded by awfulness on both sides. The Royals are finally at the point their fans thought they'd be five years ago, and it looks like they may peak there. The Nats certainly don't look like they are having the long-term, sustained success that many envisioned at this time last year. tl;dr Parallel fronts >>>> building the foundation first