If the Moshiach does not appear by the year 6000, what does that mean for Judaism?

Hello. I was recently watching an interview with an Orthodox rabbi where he indicated that it is a Jewish belief that this world will last approximately 6000 years and that the Moshiach is expected to come before that time is up. I’m wondering what it would mean for Jews if that for some reason doesn’t happen? Will the foundations of Judaism be shaken?