You are right that there is still a long way to go. BTC has drawbacks that require improvement before going mainstream. Will those drawbacks be resolved? I don't know. I don't know much about it, but maybe transactions will become cheaper once Segwit2X or further improvements kick in. Right now, transaction fees are high because the higher fee you pay, the earlier it gets picked up into a block to be processed. Otherwise, there will be other cryptocurrencies which will be technically stronger and hopefully get a bigger adoption.
RE: The elephant in the Bitcoin room. Please read till the end :)