There are several things that can destroy Steemit, but all of them are internal. Community destruction by the rules imposed.
Everything external can only make Steemit stronger.
However, there again, is a chance for self destruction by not keeping up. By not maintaining an appearance of moving forward.
So, i am with you. Steemit could really use some real competition. Because there are a lot of areas for improvement. And competition really makes two better platforms instead of a single poor one.