Required knowledge and capability has not become diluted. Some of the younger guys going through the command process are very capable, trust me. Experience? Yes. Maturity? Sometimes.
A few tech questions about systems or even better a discussion during the cruise about "what would you do now if..." usually throws 2/3 of them off because they haven't read it in the SOPs.
Some guys are capable but nowadays it is the minority, trust me.
Maturity?The one you can expect from a 25 years old.