Striking technique is over rated at the elite level

[BowserJr]

4 main factors in the examples you gave

Having to train and be ready for takedowns
Very good Spacing & timing which can be trained. This can be good while thrown strikes look bad
God given granite chin
God given KO power

 

[GordoBarraBJJ]

Small gloves can make up for shitty technique, especially at the higher weight classes were everyone has the size to put up decent power.

Hands wrapped, small gloves = bricks for gloves.