That the original Star Wars cast, or more accurately the main trio, has been killed off in effectively the span of a few days to a week in the Sequel Trilogy? Han bites it in TFA, and granted that was what was going to happen considering how Harrison Ford really wanted Han to die, and then Luke dies at the end of TLJ. Leia could possibly live longer, but she will either not be mentioned in the next film, or handled with either a throw away line like Ackbar, or in the opening crawl. But effectively the original cast has been wiped out, with the remaining cast being R2 and 3PO who are relegated to about the same amount of screen time as say Ackbar or Madine in ROTJ, and Chewie who is sort of just Rey's wingman now.
As for the time span I used above, it is based upon the fact that Han dies before Starkiller base is destroyed, and Luke dies at the end of TLJ which takes place hours if not days after TFA. We know this due to how in Battlefront II, it is canon, has it where the main character from the game see the destruction of Starkiller Base and then jump to D'Qar and are given a mission and aren't even given the opportunity to land since the Resistance is so busy packing up their stuff to abandon their base. So, the question is how long it took them to pack their stuff up and get away, since we know the FO shows up before they finish at the start of TLJ. And considering that TLJ establishes that a Resistance Transport module can make the jump from one end of the galaxy to the other in less than a few hours, thanks to the 18 hour plot, and get back after spending some time in jail it isn't so far fetched that the FO which is closer could get to D'Qar shortly after they learned of the base's location.
