If time were only part of the equation

Update:
No confirmed time travelers showed up to the Time Traveler Convention tonight.

I think this conclusively proves that time travel will never be invented, since the denizens of the future have literally all the time in the world to find a way to get to May 7, 2005, and they failed. But this raises interesting questions: Is it still necessary at this point to store the information about the convention in safe places where future time travelers will find it, if we know that they're not going to show up anyway? And suppose they had shown up - it was not yet determined at the time of the convention whether the records would be preserved into the future. Was the mental intent at that time of preserving the records sufficient to make time travelers from the future appear at that time? According to the scholarly work Bill and Ted's Excellent Adventure, apparently yes. And conversely, now that we're having all these doubts about whether it's necessary to preserve the convention info, is that sufficient to make the time travelers not have shown up?