Golos.io is actually a fork of the STEEM blockchain, and in my opinion a failed attempt at it. That being said, I do not think that anyone should be sweating competitor starting to pop up. It's always a good thing, it means that innovation on the field has not seized and that is a net positive.

There are talks of a STEEM 2.0 on EOS and maybe that is something that could shake up the waters a little bit, but in truth, the most important element of a cryptocurrency project is it's community. If the main bulk of the community remains engaged on STEEM or for a,b,c reason moves to another platform that would be the catalyst of "failure". Is that likely to happen? Probably not...