原厚 both related to mountain and rock, 原 is yuan2, spring, water,厚 is generous, since 原 has source, 厚 is not related with this, Mao 原本穷末researched da4 ben3 da4 yuan2, his theory is not dead as Wang Ming, whom my grandfather knows well, laughed at him recalled that Wang once held a meeting at two classroom for no a larger hall is available, he stood at the corridor as a host, saying that Wang's small wit is no more than this trick. Mao's feet stands on a firm ground,this is the reason he won in1949.

厚积薄发: 1.A profound knowledge prepares a half done well begun! ...
2.to be so well versed in a subject as to be able to write about any part of it with ease.
I think both are not well translated.

厚积薄发 should aim at 原, 原本穷末, otherwise has no 厚-degree at all, is only 薄积薄发, it is like a building without a ground. So, I place 原 ahead of 厚, 原本穷末 ahead of 厚积薄发, in order to pursue of 原, Mao planed to trace the source of the Yellow River. We as Engligh learner should have a basic knowledge of etimology in order to master a 厚
vocabulary.This what I'm doing now.

厚德载物, Here 原 can not replace 厚, since it is long vs. high, original vs. generous. We see some leaders are lack of this character after they are in high position. Their positions were rocky, because they are not hou4 for they disconnected with yuan2.