It’s for everyone who would ever read it, but when Jesus gave a particular people a description of what they could expect during the Tribulation, who was he directing that to - at the time of Matthew 24?
He could only be directing it to those who would be alive here on earth on that last day. That day when there is the sign of he son of man coming in the sky.
Jesus didn’t give a particular set of people the prophecy of what they would be seeing on that last day. He gave that prophecy to everyone who would be here on that last day. And that prophecy has been read for 2000 years now. Maybe by some who will be here on that last day... and maybe not by any of those yet.
When the Angel spoke to the shepherds in the field, who was the angel speaking to? Just the jewish shepherds? No, the bible is relevant to us today.