It is a holy week in every gamer’s calendar. Each June, 50,000 members of the video game industry descend upon Los Angeles for the Electronic Entertainment Expo, or E3, the industry’s most-anticipated trade show. E3 often features the unveiling of big titles and celebrity appearances from the likes of Paul McCartney and Rihanna.  Now, however, E3 is in flux.  Some publishers have walked away from E3 2016, which is set to begin next Tuesday. Electronic Arts, the company behind titles like Medal of Honor, will not be there and is instead hosting its own mini-expo the same week. Activision, which publishes Call of Duty, chose to forgo its booth at E3 for the first time since 2010. Disney also will not be there after the company announced last month that it was shutting down its video game publishing business.  The Entertainment Software Association, which organizes E3, plans to fill the gap with virtual reality and mobile games. This year’s show will have more than 90 mobile gaming exhibitors and a pavilion dedicated to online and mobile games, while 53 exhibitors will showcase virtual reality tech, up from 27 in 2015.  The changes spotlight how E3, which once defined the most innovative and exciting developments in games, is working to remain relevant in a shifting industry.  In the past, E3 brought publishers, retailers and the gaming press together to provide a sneak peek of new games for consoles and PCs. But the rise of digital distribution services and free-to-play mobile games has made physical game stores increasingly obsolete. And many publishers can speak directly to gamers via social media and video-sharing platforms like YouTube and Twitch, making it less necessary for companies to wait for a yearly event to tell gamers what they have been up to.  “To my eye, E3 is being overtaken by much better channels to gamers and the online-ness of great games themselves,” said Bruce Hack, the former vice chairman of Activision Blizzard, who now works as a consultant. “E3 is not yet fossilized, but its unique position is eroding.”  Rich Taylor, a senior vice president at the Entertainment Software Association, said E3 evolved every year and remained “the launchpad for remarkable advancements from the fastest-growing sector of the entertainment industry.”  The forces that E3 contends with are evident in the numbers. Sales of physical games — discs in boxes — are declining. This year, mobile gaming revenue will overtake that of PC games for the first time, according to a report from Newzoo, a game research company.  With digital distribution of games on the rise, “the importance of retail has weakened,” said Itzik Ben-Bassat, former executive vice president for global publishing at Blizzard Entertainment. Blizzard publishes World of Warcraft, one of the most popular massively multiplayer online role-playing games.  “As the market structure has shifted, E3’s importance has been in constant decline,” said Mr. Ben-Bassat, who now runs Gong, a trending news site and app.  This is not the first time E3 has undergone a metamorphosis. In 2006, the association scaled back the show after attendance hit 70,000, to eliminate overcrowding. It was reintroduced in 2007 as an invitation-only event that took place largely in hotel conference rooms — and was rapidly denounced for what was seen as a lack of energy and excitement. That format continued for another year before a flashier E3 was reinstated in 2009.  Yet even as E3 returned to its revelry-filled self, sometimes featuring lavish parties and concerts by Usher and Eminem, game publishers began chipping at the show’s dominance by holding their own events to reach consumers directly.  Blizzard, for example, has created its own annual event called BlizzCon, held in Anaheim, Calif., usually every November. BlizzCon, which the company uses to promote its major gaming franchises, is open to the public; last year’s event attracted more than 25,000 people.  “After many years of continuing to grow our audience around the world, we thought it would be cool to provide a way for our employees and players to be able to celebrate their passion for Blizzard games together,” a Blizzard spokesman said.  E3 also faces increased competition from fan-focused expos and conventions like Comic-Con, the Penny Arcade Expo and MineCon, the annual Minecraft convention held in a different city every year.  Interest in getting closer to consumers seems to have at least partly motivated Electronic Arts to split from E3 this year. The company’s new event, EA Play, will start two days before E3 at a venue inside the L.A. Live entertainment complex, within walking distance of the Los Angeles Convention Center, where E3 is being held.  EA Play will include news conferences, playable versions of featured games and opportunities for gamers to speak to the developers behind coming titles.  “The necessity to bring all retailers in one place is less significant today than it was 15 years ago,” said Chris Bruzzo, Electronic Arts’ chief marketing officer. “We see an opportunity for us to try some new things that reflect where the company is going.”  Mr. Taylor of the Entertainment Software Association said it was not a coincidence that EA Play was being held the same week as E3 and in a nearby venue.  “Companies have come in and out of the show for years,” he said. “Consistently, people find ways to attach themselves to E3.”  At the same time, the association is trying to diversify its events. Last month, the group said it planned to hold a public event called E3 Live alongside E3 for the first time. The free event will serve as a kind of mini-E3 where gamers can interact with industry types and play games. More than 20,000 gamers are expected to attend.  “The attempt to open it to the public is maybe too little too late,” Mr. Ben-Bassat said, “but it is indeed the right direction for E3 to survive.”  A version of this article appears in print on June 9, 2016, on page B1 of the New York edition with the headline: Once a Video Gamers’ Show, E3 Brings In New Attractions. Order Reprints| Today's Paper|Subscribe
E3 has lost some industry participants in what was once a premier event, but it is adjusting its lineup and adding an event for gamers.