There is always more stuff to know about medicine. Sure, you get more experienced with the common things, and better-able to do procedures, but there is always more. Even if you somehow managed to abruptly memorise all of human knowledge about medicine, within 5 years a goodly portion of it will be out of date. New drugs, new trials, new evidence and new syndromes crop up all the time. As a relatively new doctor, I am picking up tidbits of this new information on a daily basis.
Take then the example of the old consultant. They have vast reams of experience behind them, a tried-and-tested, in-depth understanding of their field. They are, in every meaning of the word, an expert. They have spent years doing a thing, which makes them good at it – but is also a limitation. The old guard consultants can hold things back. They may not trust a new drug, or believe that an old treatment which has now been demonstrated not to work is still valid. They may not trust a new electronic version of something which they have always done on paper. Their vast experience leads to vast influence, and they may thereby hold back progress on a scale which can extend to the entire hospital.
I’m not saying this is common, but it happens more often than it should. The ponderous generational shift in practice driven by the retirement of excellent-but-flawed consultants doesn’t fit with the rapidly-changing nature of medicine, and that is another thing that needs to change.