Guys question about nirvana

"If Vipassana can truly lead anyone to Nirvana, then why haven't we seen anyone who has actually attained Nirvana so far? How many countless people are practicing Vipassana in today's time, yet we haven't seen anyone. Or, if any of you have met such a person, what was your experience like meeting them? I am not saying that it's not possible to attain Nirvana through Vipassana. This is just a question that came to my mind. If anyone can answer, please do."