* World War II. In WWII, the only country that had the means to meaningfully fund longer-term military research projects was the US; in other countries such as Germany and the UK, these projects were defunded or reduced in scope to let the money and resources be allocated to things that would help prevent the collapse of the country. Furthermore, the US was the only large country to escape significant infrastructure destruction, which would preoccupy most of the rest of the world for another decade or so.
* The development of a strong education and research system. This is in and of itself a more complex topic, but one thing I'd call out is that the American wealthy have had a stronger tradition of philanthropy than their European counterparts, and a lot of that philanthropy was geared towards making sure that the US was well-stocked with universities, libraries, museums, and the like.
* Clustering effects. Companies tend to want to be near other companies that do similar things--it's why there's a lot a tech companies in Silicon Valley, even if they could do their job equally well from Illinois. Early computer research ended up being in the US, so the computer technology clusters have ended up being very US-centric.
* Market size. The US has historically been the largest market for tech, and arguably still is for certain segments of the market. Europe has been (and generally remains) too fragmented to be a single market, China and India historically too poor, and the USSR hampered itself with internal controls. Furthermore, the size of the US market also means that it tends to be harder for foreign entrants to break into the market than it is for US entrants to break into foreign markets.
> Do you think another country will take its place?
Eventually, yes. On what time scale, I can't say.
> Will growing internet adoption lead to growing patterns of geographic decentralization in the industry?
No. The internet has not reversed the trend for businesses to cluster together, and I see no reason to expect that should change.
> Is it possible cryptocurrencies will cause a rise in an internet centered tech industry?
I don't see how they could...