Coaching was always important. Great managers in the past have always done coaching, whether it was formally or informally. The difference, at least from my experience, was that managers in the past saw coaching as something that was nice to do, but not necessarily required. Today, managers HAVE to be effective coaches.
This is due to a combination of things: the pace of change in the world and the access to information.
Anyone over the age of 40 (maybe 35) knows that the world is changing at lightening speed. A career path that was nicely structured now is a jumble of zig-zags and dead ends. Technology that was non-existent 5 years ago is now a “must have” for a professional. The only possible way to keep up is with a coach - an expert in an area that can help us get up to speed quickly.
This is where access to information becomes an issue. I love and welcome the fact that there is so much information out there. I can pick any subject I want and find a ton of information to help me. The issue is that it becomes overwhelming. I type “making rye bread” in Google and get over 16 millions results. This is why people only look at the first page of Google, because it is easy to get overwhelmed. A good coach can help you cut through the mess - this resource is credible, that resource is too basic and won’t help your issue, etc.
To be a great manager, you CANNOT coach your team on everything. You just don’t know everything. But you can coach on the things you know (which is likely to be needed by at least some of your team) and you can connect them with other coaches who are experts in different areas.
One last note: in the past, managers who were coaches were a luxury. Now they are a necessity. If you can’t or won’t coach, you will never be a great manager.