No, what technology you work with doesn't really determine anything. When I started working for a dot-com back in 1998, I had never used classic ASP or knew other technology advancements that would change how I do my work.
What determines long-term growth is knowing what you want to do and can do well. Do you want to build systems? Do you want to build UI components or database components? Wherever one's strengths lie, that is the key to unlocking one's potential. After all, were there iPhone developers 5 years ago, outside of Apple? Whatever is top dog one day may not be top dog down the road,e.g. look at the history of Yahoo!, Netscape or AOL if you want some former Internet titans that have lost a lot of their power from where they originally were positioned. What mobile platforms will we have 5 years from now? Will there be a company that can claim a majority of market share among smartphones,e.g. could Android become huge or will it be a fad? Will SEO still be a big field 10 years from now or will something come along to replace it? These are just general rhetorical questions to ponder.
While I've only been working since 1998, there have been a lot of things that have changed, but there are also some things that haven't changed like I still use a version of Visual Studio, Internet Information Services and MS-SQL Server, though their guts have changed tremendously in the past decade.