it's trust. while i agree eth is one of the ONLY alts that has an active community, development and a presence that isn't just fake marketing; bitcoin has trust. it's the longest chain in crypto. it's what the whole community has been developed around. the "tech" isn't the issue with btc, it's the security. currently bitcoin has the best security of ANY crypto. as for the miners controlling ? yes and no. should a group ever try a 51% attack it can be quickly addressed by the devs after the first double spend. andreas did a talk on this very subject recently. china has a dominance in mining mostly because of the cheap energy in the rainy seasons. BTC