It's not that simple. In the end it's what users actually use that matters. Mining on a fork that sees no use would be suicidal. So miners need to follow users,

It's not that simple. In the end it's what users actually use that matters. Mining on a fork that sees no use would be suicidal. So miners need to follow users, or their investment is for nothing. And users tend to follow developers, at least until there is a contentious fork. So while there is no clear single party that makes decisions, active developers have the most say.