The only reason Cruz would endorse Trump is to try to salvage his career if possible so he could later say “I was the bigger man and endorsed Trump”.
By Trump already cutting off that opportunity for Cruz by saying he would accept an endorsement if it came, it not only rubs salt in the wound, it keeps Trump from looking weak or like he needs Cruz and his ilk (he doesn’t and they both know it) and it prevents Cruz from being able to use an endorsement as his own self serving political capital.
“The only reason Cruz would endorse Trump is to try to salvage his career if possible so he could later say “I was the bigger man and endorsed Trump””
I think that too.