there are better technologies than btc but up until now, no one can beat the popularity of btc. if you've been in this forum long enough, you've seen a lot of projects offering much better performance than btc. however, most of them are dead already.
though there are indeed better projects out there, the question is, how are they going to cope up with BTC's popularity of usage? though we have several top alts to offer the shortcomings of btc, still people go back to btc because it is the trusted one in this market.
Those better performing Alts are not able to provide better outcomes because of one and only reason. They are centralized. And people involved with bitcoin knows what freedom means and the true potential that Bitcoin could bring to them in the future.
If something could be controlled by someone and could be manipulated, then no wonder people will try to stay away from them. Many choose the Alts to make quick profits. ICO, token sale, trend all that to use it at their advantage in order to make quick profits from Alts. But when they think that those centralized Alts are at risk, they eventually come back to Bitcoin. This is how powerful Bitcoin is.