I'm not sure we are really disagreeing because you are addressing a different question.
I agree that the goal should be to try to win it all. But, the question you asked is whether as a fan I would rather have one World Series and decades of mediocrity or several seasons of contention.
Put, another way, would you be happier today as a 73 year old fan of the Marlins living off the glow of two World Series wins over 20 years ago, or a fan of a team that for the last 8 or 9 years, and a few others before that, has allowed you to follow the team day by day looking at the standings and evaluating their chances to compete in the playoffs.
Brewers fans saw the ugly side of this from 1993-2006. Those years would have been miserable even if the Brewers had won the World Series in 1982.
Your comment about money begs the question of whether the current owner, or any owner. would be willing to spend the amount of money that would allow the Brewers to overcome the inherent revenue disadvantage of the small market. Personally, I don't think any realistic amount of money would significantly increase the Brewers chances of winning a World Series while competing against the likes of the Dodgers, Yankees, Mets, Red Sox, Phillies, Giants, Cubs, Astros, et al.
There's a reason why only 13 of the 30 MLB teams have won the World Series in the 21 years since the Marlins surprise win in 2003,. Only the Royals in 2015 would be considered "small market" even though their market is much larger than the Brewers'. It isn't that the other 17 franchises aren't trying to win. Even some teams in much larger markets have failed to win while throwing around a lot of money.