Those are two different questions.
1) You ask, "Do you think there will come a time in the near future when DeWitt desires to build a dominant roster again?"
2) You ask, "one that isn't dependent on individual optimal outcomes to have a shot at winning a World Series?"
Answer: That doesn't exist. No one wants to hear it, but every team that wins the World Series is based somewhat on hope, even the Dodgers, who had to trade for Scherzer and, during the season, added a DFA'd Pujols to the mix because of injuries, and they made other moves based on the hope that they would out and make them a World Series title. Every roster is built based on getting optimal results in order to have optimal outcomes. The best rosters either have depth to adjust when that doesn't happen, or a front office that has the creativity or pocketbook to correct the mistakes.
The Brewers had a roster built to count on optimal outcomes to contend for the division title. And when they didn't get it, they traded for Adames and hoped he'd be the answer.