When people revert back to their bad habits in their fights, it means the technique was drilled enough, and it wasn't drilled enough in a live environment. Its a reason why it is key that the most simple and rudimentary techniques and tactics get ingrained in the short time the camp lasts for.
There just isn't enough time to cover the myriad volume to techniques in the short amount of 8-12 weeks, even then its really 7-11 weeks because by cut week you're done, there's no improving on there, its just water manipulation week.
Foreman threw them early in the fight against Ali. He liked mixing in layman shots to take advantage of his big arms. I'm guessing thats why. Just throw the kitchen sink at him.