I think many wouldn't be keen, but they would do it. It is harder now though of course, as there are checks and balances in place. A 51% attack isn't buying Ned's stake and convincing exchanges to power up (well after the coming HF for the exchanges).
The question will really become what is the point to attack, since there are no resources that need stay?
Some people would like the windfall, but that ends too once it becomes so common that there is no value, so eventually attacking becomes useless because it can force a fork, but there is also no windfall for the fork other than freedom - so both sides look to maintain and generate value on the chain. Once the ecosystem is large enough, it becomes very, very expensive to attack, so why risk it?