Fans will still have to be patient, said Epstein, Cubs president of baseball operations, who met with the media one day after the team wrapped up the season at 61-101.
"Having not been here previously, I think there was a real improvement in the culture around the team and the mood around the clubhouse," Epstein said Thursday at Wrigley Field. "Despite being a losing club -- and we can't get away from that, we were a losing club -- there was a real professionalism, a real spirit of unity, a real effort to play hard every day, to have each other's back, to prepare.
"We had our lapses," he said. "We had plenty of bonehead plays on the bases and things that shouldn't happen, but on a whole, it was more of a winning atmosphere than you typically see around losing clubs. That's something we can build on, that's something we're going to expect, that's going to be the standard, that we can continue to build off of."
A lot of the credit for that change goes to first-year manager Dale Sveum and his staff. That could make the Cubs more attractive to free agents. Epstein said they will be looking at free agent pitchers to fill some of the holes in the rotation created by the trades of Ryan Dempster and Paul Maholm.
"Players want to play for certain managers," Epstein said. "I guarantee you, starting today and throughout the whole winter, players will be talking about how great it is to play for Dale Sveum and be part of this clubhouse we have here.
"I've also heard that players want to be part of the solution here, and want to be part of the club that ultimately wins a World Series here," he said. "We have an opportunity as well. With a certain tier free agent, we can sell opportunity.
"I think Paul Maholm would tell people he's really glad he signed here. ... I think he feels good about his Cubs experience, and would come back here in a second if he got the opportunity."
Epstein would prefer the roster was 100 percent homegrown. But some of the top prospects need more time. Josh Vitters and Brett Jackson, who struggled in two months with the big league team, were both told they will open next season at Triple-A Iowa.
Epstein said Vitters has had a tough time initially at every level he's advanced to. The third baseman hit .121 in 36 games with the Cubs. Jackson's swing wasn't ready, Epstein said, but they wanted to promote the outfielder so Sveum and interim hitting coach James Rowson could work with him. Jackson finished at .175, with 59 strikeouts in 120 at-bats.
"I think he'll have a much more productive offseason because of what he was exposed to than if he had stayed at Triple-A," Epstein said.
Rowson, who took over in May when Rudy Jaramillo was dismissed, will either remain with the big league team or could return to his duties as Minor League hitting coordinator.
The 2012 season is significant because it's the year Anthony Rizzo, Jorge Soler and Albert Almora joined the organization, Epstein said. Rizzo took over the No. 3 spot in the lineup when promoted from Triple-A on June 26. Soler, a 20-year-old Cuban outfielder, signed a nine-year, $30 million deal in June, and Almora was the team's first-round pick in the First-Year Player Draft.
Other highlights for Epstein included Javier Baez, the Cubs' No. 1 pick in 2011, who made progress in his development; Darwin Barney, who proved to be one of baseball's elite defensive second basemen; and establishing the scouting and player development infrastructure.
The Cubs drew 2.8 million fans this year, the first time they did not reach 3 million since 2003. Fans can expect more growing pains.
"I'm not going to sit here and say, 'Don't worry about 101 losses because we have a magic plan to win the World Series in 2013, and it's going to happen -- be there now,'" Epstein said. "I think what we're trying to communicate is there is a plan, there is a vision. It might be a little bit longer term than we all want it to be, but we're committed to it. There's great reward at the end. You can't guarantee results. But I'll tell everybody, we won't be satisfied unless we're in the postseason year in and year out."
Perhaps the biggest surprise, he said, was veteran Alfonso Soriano, 36, who hit 32 home runs and set a career-high with 108 RBIs.
"Coming in here, I actually had a little trepidation of how we'd handle him and the contract, and if his skills declined, how we'd handle playing time," Epstein said. "I'll be honest, it wasn't something I was looking forward to. Those concerns proved to be completely baseless. What a pleasant surprise he turned out to be."
However, Soriano's trade value is high. He has two years and $38 million remaining on his eight-year contract, but also has 10-and-5 rights.
"If teams pursue him in a trade, we'll consider it," Epstein said. "If we trade him, we're losing something, so we have to get something back in return to justify that."
Despite the losing record and long hours, Epstein did enjoy his first summer in Chicago, saying it was a very livable city for him and his family. After a company softball game Friday, it's back to work for 2013.
"My hope is that years from now, when we're celebrating successes year in and year out, we look back at 2012, and say, 'Look how far we came,' and I think we will," Epstein said.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.