From what I hear of the Donald, he only issues these kinds of punches if punched at. There’s respect between the Donald and certain others, e.g. Ted Cruz. Donald isn’t worried about low ceilings on those he floors for attacking him.
If Trump should happen to win the Republican nomination, it will not help his cause if he has insulted and alientated most all of his opponents and their supporters. His style puts off as many people as it attracts, and probably more so. It doesn’t bother his hardcore supporters (the “high floor/low ceiling”), but it does bother many outside that group, including many conservatives.