Of course there is. However, as Bitcoin Classic may illustrate, it is possible to leave the core developers working on a defunct chain.

Core developers represent a double-edged sword. They are critical for getting the network adopted, and for adapting the network to new demands, but they can also be a risk due to their influence. By all accounts, the Ethereum core developers have been open and responsive. Not all Ethereum devs wanted this fork. I do think they could be faulted for not strongly advising Slock.it to cap The DAO. That may be one reason why they were amenable to a refund solution.

You definitely should consider the core devs when investing time and money in a blockchain. They have an inertia that influences the system.

Influence is like money. You have an equal right to pursue it, but no right to some quantity of it. Some people have more of it, others less. If you want more, you're gonna have to work for it first.

In the ability to propose a hard fork, no difference. However, you need to be able to convince the majority of miners to vote for your fork and that's where being a core dev has a lot of influence.

Apparently, the core developers could rally a quorum and gain consensus. Perhaps you could not.