Those aren't mutually exclusive ideas. Signing a 28 year old first baseman who's one of the best hitters in the game and a 31 year old pitcher who has less mileage on his arm than the vast majority of 30+ guys is building a longterm contender. Pick up those two fill in young stars like Castro and Soto and solid young players like Jackson, McNutt, Szczur, Whitenack, etc., coming up and you have the makings of an extremely good team going forward long term. And at the same time adding Fielder and Wilson gives us the tools to be competitive next year as well. Tearing the current team apart and eliminating any chance of contending for 2-3 years is pointless for a team that can win as soon as next year, while at the same time bringing in the pieces to be serious contenders long term.