The death of Apple's inspirational leader is likely to have a deep impact on the technology giant behind the iPod, iPhone and iPad, giving rivals a greater chance of catching up.
Steve Jobs' creative spirit was so closely tied to the fortunes of Apple that his death raises questions about the company's ability to keep its pipeline of transformational products running at such a fast pace.
As a technology analyst, I am sorry for his death. It was Jobs' Apple, not Apple's Jobs, said Kim Young-chan, an analyst at Shinhan Investment in Seoul.
The CEOs of rivals including Samsung Electronics, Amazon, Google, Nokia and Sony mourned the death of Jobs, a sign of the respect they held for the Silicon Valley legend.
Jobs, who was 56, had fought a long battle with pancreatic cancer. In August, the man known for minimalist design and marketing genius handed the reins of Apple to long-time operations chief Tim Cook.
Cook unveiled the latest version of Apple's iPhone this week, in a launch that, unusually, failed to wow fans.
The tragic passing of the company's influential leader and the industry's mixed response to the recent iPhone 4S model create challenges for Apple in coming quarters, said analyst Neil Mawston from Strategy Analytics.
Industry eyes will inevitably turn to the iPad 3 launch next year to see whether Apple can continue the company's impressive legacy of innovation created by Steve Jobs, he said.
In a sign of stiffening competition, Amazon.com Inc took the wraps off its Kindle Fire tablet last week, tacking on a mass market-friendly $199 price tag that analysts said poses a serious threat to the iPad.
Apple is facing a competitive fire storm from not just one company but a coalition of rivals that are trying to beat it, including some of the largest consumer electronics companies on the planet, said Ben Wood, head of research at British mobile consultancy CCS Insight.
Analysts have said the South Korean conglomerate Samsung is one of the best placed companies to deliver something fresh and exciting to rival Apple. It already makes the closest competitor by sales to Apple's iPad tablet.
Samsung Chief Executive G.S. Choi said in a statement: Steve Jobs introduced numerous revolutionary changes to the information technology industry and was a great entrepreneur.
The two companies are scrapping for top spot in the smartphone market, having overtaken Nokia, the market leader for the past decade, earlier this year.
Apple is also Samsung's biggest customer through the sale of mobile chips and display screens.
The relationship and rivalry has helped Samsung become a top global brand over the past decade with a stock market value of $115 billion -- still modest compared with Apple's $345 billion.
But the relationship has also produced tensions over mobile devices. The two companies have sued each other in 10 countries involving more than 20 cases since April.
Samsung's Galaxy range of smartphones and tablet computers run on Google's Android operating system.
Steve Jobs was particularly passionate about the enforcement of Apple's intellectual property, said Florian Mueller, an intellectual property expert. From a strategic point of view, Mr Jobs' successor doesn't have a choice other than to fight equally hard.
Jobs liked to make him competitors uncomfortable. Rivals were flummoxed by the iPad, he declared in March when he took the stage to unveil Apple's latest tablet.
They went back to the drawing boards. They tore up their designs because they weren't competitive, Jobs said.
Lee Seung-woo, technology analyst at Shinyoung Securities, said Apple had transformed the industry, but its influence would wane without Jobs at the helm.
Under Jobs, Apple consolidated segmented IT sectors into one big consumer market and claimed so many victims, Lee said. Without Jobs, Apple's rivals now have some time to step up and majors such as Google, Samsung, Microsoft and Facebook will try to fill the gap.
Jan Dawson, chief telecoms analyst at research consultancy Ovum, said Apple would do well in the short term as the company would roll out products Jobs had a hand in.
The iPhone -- introduced in 2007 with the touchscreen template now adopted by its rivals -- is the gold standard in the booming smartphone market, and its sales have dealt a blow to the ambitions of many competitors.
The question is whether it can continue to launch iconic and successful products without him ... In the longer term, Apple risks becoming a more ordinary company without him, Dawson said.
Howard Stringer, the chief executive of Sony Corp said: The digital age has lost its leading light, but Steve's innovation and creativity will inspire dreamers and thinkers for generations.
On Thursday, Samsung's shares rose 1.5 percent, LG Electronics advanced 6.3 percent, Sony rose 4.7 percent and No 3 smartphone maker Nokia was 2 percent up.
Jobs was an outstanding CEO and his successor Tim Cook faces a test (as to) whether Apple will be able to lead the global market as it was before, Lee Jun-hyuck, a fund manager at Dongbu Asset Management.
Phones based on Google's Android, which is available for free to handset vendors such as Samsung, HTC, LG and Motorola, now have a greater combined market share than Apple's iPhone, which is still the world's No. 1 selling smartphone.