Stockholm has produced a few successful startups, but it's not a competitor to SV. It's is a global competitor in telecom systems and games (though I guess many game companies are now owned by US companies). Spotify is basically the same service as when it started, just with more users. Stockholm has no real momentum in building something of their own.
There is a huge difference between the valley - home of the whole industry and Stockholm, which hosts a few niched companies.
Compare the hiring. In Sweden there is no demand for CS skills, there is no immigration programs for techies, etc.
Also, which is also important, Sweden is traditionally a consumer of technology, not producer (with exception of Ericsson, of course) - MS land where Linux is frowned upon outside academia and almost nonexistent in the market.
There is not even a dim analogy to what is going on in the valley.
http://www.forbes.com/sites/knowledgewharton/2015/11/11/how-...