I don’t feel the ratio is as literal as it seems. It’s not that a certain individual is 30% competent technically, it’s that that person’s overall success is relying on their technical knowledge 30% overall. For example, person A is very skillful technically, however they insult everybody that they meet. That person will be less successful because no one will want to work with/help them. Person B, having the same technical aptitude as person A, will be more successful if they have better interpersonal skills. Realistically, the 70:30 ratio makes sense being that effective interpersonal skills allow teams to work more efficiently and with a higher morale.