AS for Cruz belatedly endorsing Trump, although Trump was very statesmanlike and said he wouldn’t accept a Cruz endorsement, I’d have said: FU Ted.
Cruz is only caving now because he is seeing that his “principled” stand is imploding and his political career is about to go dead and out.
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.