Howard R. Gold

Special for USA TODAY

Starting Thanksgiving Day, Americans will head out en masse to "door-buster" sales at the USA's biggest retailers.

Flat-screen televisions will be among the hottest items: Walmart stores are offering a 65-inch Vizio LED HDTV for $648, and Best Buy a Samsung 55-inch LED for $599. According to IHS, televisions will be on one-third of U.S. consumers' shopping lists this holiday season.

But Black Friday's frenzied buying masks tectonic shifts in the $207-billion consumer electronics industry. Mobile devices are upstaging traditional TVs in what could be the biggest change in mass entertainment since television supplanted radio and the movies after World War II.

2014 could mark the second consecutive year of declines in television sales. DVD sales are plummeting and Blu-ray, once the industry's great high-definition hope, has plateaued.

Meanwhile, smartphones, tablets, and streaming-video services are surging as "cord cutting" from cable or satellite TV accelerates. More consumers now value mobility and sharing over the picture and sound quality that marked the home theater era of the 2000s.

"We're at a very interesting inflection point," explained Sean DuBravac, chief economist of the Consumer Electronics Association, an industry trade group based in Arlington, Va.

"No product has ever been as successful as television. TVs were the largest revenue category for consumer electronics for a very long time — we can easily say, for the last 50 years."

But now, said DuBravac, "televisions are definitely a mature market. People are not adding more units to their households."

Televisions are in 99% of U.S. households, which average 2.9 sets each.

But one group — Millennials — appears to be cutting the cord in particularly large numbers.

Back in 1991, The New York Times noted that in college dormitories, "televisions are nearly as common as stereos."

Fast forward to November 2014, and the Times reported that a Tufts University student found the presence of a TV "a little bit weird" and that 90% of her friends had never owned one.

While television sales decline from their peak of 40.3 million in 2012, smartphone purchases have tripled since 2010, to an estimated 163.5 million this year. Since 2010, tablet shipments have skyrocketed almost 700% to an estimated 80.4 million units in 2014, according to CEA.

"For right now we see a generational shift in adoption of technology," said CEA's DuBravac. "Whether that maintains as consumers age remains to be seen."

Meanwhile, physical media look to be in permanent decline. Sales of Blu-ray players should remain steady at around 11 million, but they're in only 31% of U.S. households compared with DVD players' 95% penetration at their peak.

In 2013, sales of video discs were less than half of the $20.2 billion worth of DVDs sold in 2006, according to the Digital Entertainment Group.

A report by PWC earlier this year predicted streaming-video services like Netflix and Hulu would earn more than movie theater box offices by 2017.

Another popular holiday gift, digital cameras, have seen shipments plunge 33% through September, reported the Japan-based Camera & Imaging Products Association.

Point-and-shoot cameras are in free fall as picture quality on iPhones and other smartphone cameras improves. Shipments have fallen by more than half since their 2010 peak.

"The value in using a mobile device is the value to share it immediately. They've passed the 'good enough' threshold," said Christopher Chute, vice president of digital imaging practice with Framingham, Mass.-based market research firm IDC.

"That whole consumer side of the market is now the phone camera. You have all these options and they're very accessible from the device you carry in your pocket every day."

That's happening throughout consumer electronics as traditional home entertainment gives way to a new age of mobility, sharing and convenience.

Howard R. Gold is a MarketWatch columnist and founder and editor of GoldenEgg Investing, which offers simple, low-cost, low-risk retirement investing plans. Follow him on Twitter @howardrgold.