This is the consequence. Many different factors influence this "increasing/decreasing demand", like you said: news, technological development, projects development... I would add instability in countries economies as well, it's a good factor that affect Bitcoin's demand and price.

When people have a weak local currency and a weak economy they will look for new ways to earn money and if possible, new currencies to keep their money.
You can see Venezuela as an example, Crypto-Currency is becoming very popular there, especially because their local currency is very devalued.