if anything can cause a big drop followed by a long bear market like 2013, then it is the high fees that bitcoin currently has. which is causing bitcoin to lose market dominance.
I'm not so sure about that. Can you point to any historical correlation between fee increase and price decline? On the contrary, fees rose all throughout 2017 and......so did the price.
If high fees are causing Bitcoin to lose dominance, I suppose Lightning may grab that dominance back?
people always focus on market cap as dominance which is absolutely useless. but the real market dominance of bitcoin has always been the merchant adoption of bitcoin as a currency which helped with the more adoption and the rise so far. in fact the big rise of 2017 was initiated by Japan adopting bitcoin as a currency.
"Merchant adoption" is so 2014. What has always mattered is
user adoption. Bitcoin's value is based on it's network, not the number of merchants that accept it and immediately dump it for fiat.
with high fees bitcoin is losing (and will continue losing) merchants and with it market dominance. and the damage may not even be only to bitcoin but to the whole market. imagine merchants accepting an altcoin and that altcoin fails too. either a simple high fees like bitcoin or worse a bug in it which leads to millions lost. (both happened already with ETH for example).
No one has really solved the linear scaling problem yet. Ethereum will likely implement sharding and will have the Raiden Network. Bitcoin will have sidechains and Lightning. Other solutions haven't been tested at scale or require centralization. IOTA's tangle comes to mind.
We have to face the fact that all this speculation outpaced the actual utility of these blockchains.