Speaking as a block producer: With the current amount of network utilization it would not make short term economic sense to support the network. But if STEEM's value were 0, the amount of people using it would greatly diminish. Resource requirements would be vastly reduced to the point where much less expensive servers could handle it. If there was a chance of recovering it's value, it would be a very sound economic decision to ride out the storm. STEEM's value fell to about $0.06 USD once and those who didn't quit then have been rewarded well.

As a person, the non-economic qualities of the blockchain are great positives to me: censorship resistance and decentralization of a text/informational database are cool and a useful thing to have on the internet when tyrannical governments are leveraging the internet more and more to maintain control of their citizens victims.

does the platform offer much if you remove the rewards?

It's a valid question that has been asked multiple times. The glaring issue is that Steemit is the most-used front end for the Steem network. It is this way because it was the first, and for a long time the only, usable front-end. So it has that inertia. It also is the place where most people come to get an account, adding even more stickiness.

In April 2016, the Steemit website was functional (barely sometimes :P) but it felt a bit like a placeholder. It was very spartan. Only basic features were implemented. The problem is that 2 years later, though enough features have been implemented to make it just usable enough, it's still like that early placeholder.

Some important features have even been taken away. The original concept of Steem+Steemit was to be a bit of a Reddit-killer. But one day, without too much thought given to it, direct external link posts were removed from the Steemit UI. I think the reason cited was "security." While the stakes are a bit higher than Reddit when it comes to account security, I don't think that argument holds water. Making this change has had an extreme effect on Steem user culture and expectations. It's turned what could have been a Reddit-killer into a blogging site. The culture is still poisoned with an expectation of its users to produce unique content, which is not something everybody actually wants to do. This has limited the scope and horizons of Steem and undoing the damage is a slow process.

Every time someone points out to the people that influence its development that UX for Steemit is important, beyond posting rewards, it seems like it gets shrugged off. Or even worse, excuses are made that Steemit/Condenser (the front-end software's generic name) is only meant to be a bare-bones reference implementation. This ignores the fact that it is the most used front end and has the inertia to continue to be used.