What does bitcoin have to be scared of?
Other coins with blockchains that aren't artificially limited by a corporate takeover attempt to relegate it to a settlement layer?
I suspect that bitcoin losing 50% market dominance is a major event. It's been dropping like a stone.
I think bitcoin no longer dominates the market, some recent surveys have proven that, some other currencies are rising and competing with bitcoin. Unconfirmed transactions are a major cause for discouraging people who may stop using bitcoin at any time.