Apple can't always rely on the same products to bolster sales. Another version of the iPhone can't keep propping up the company for the next 10 years. Google has been doing some great things to further technology that is brand new. Samsung is also doing well on the smartphone front. Apple will have competition and hopefully it listens to consumers and gives them what they want.
I do not believe that Apple will always be a viable company. I believe they've had a good run and some excellent products to put out there, however there recent releases are just different sizes of the products they already have. I have a feeling the age of Apple is over.
Apple for the moment is the big cheese in the area of electronics and electronic devices and communication. But that does not mean for a moment that it will hold that position. There is just too much innovation going on within this market to be able to predict such a thing.
No, I do not believe that Apple will always be a viable company, because their products are not as cutting edge as they used to be. Apple loses market share each year to Google. Apple's products are becoming tired and out-of-date. Apple needs to make sure that its products stay current and innovative, or they are going to be a company of yesterday.
Currently, due to both the current level the economy is at and the current state Apple is in, I cannot say that it will always remain a viable company. When Steve Jobs dies the stock prices took a hard blow, but were revitalized due to the iPhone 4s. However, save for the introduction of iOS 7 and a fingerprint scanner on the iPhone 5s, there have been little to no notable changes to the companies ever popular products. If this continues, the company will eventually stop producing popular products and fall into debt of bankruptcy, causing it to lose its viability.
Don't get me wrong, I love the products Apple has out right now, I use an iPhone daily and I wish I still had my MacBook Pro, but just because Apple put out these amazing pieces of technology does not mean they are destined to remain viable forever. I believe Apple had a rough time prior to Steve Jobs and I believe they will have a rough time again.