The absence of any attendees at Stephen Hawking's time traveler party in 2009 does not necessarily disprove the possibility of time travel in the future. There are several possible explanations for why no one showed up:
Time travel might not be invented or feasible in the future: It's possible that time travel simply does not exist or is not achievable in the future. While it's an intriguing concept, we currently have no scientific evidence to confirm the existence of time travel.
Time travel might be constrained to specific limitations: If time travel is possible, it could be limited to certain conditions or constraints that prevent people from freely traveling to any point in time. These limitations could include fixed points in time that cannot be altered or restrictions on the ability to interact with the past.
The invitation might not have reached the intended recipients: If time travel exists, it is also possible that the invitation to Hawking's party did not reach any future time travelers. Communication across time could be challenging or impossible due to technological or physical limitations.
Time travelers might have attended without revealing their identity: It is also possible that time travelers attended the party but chose not to reveal themselves. They might have disguised their appearance or chosen not to interact with the attendees to avoid altering the timeline or for other unknown reasons.
Ultimately, the absence of attendees at Hawking's party does not definitively prove or disprove the existence of time travel. It remains a topic of scientific speculation and exploration.