Interviewing is stupid simple. It is your ego moment. You get to sit in a room and talk about yourself. Although you don't control the conversation you can steer it in creative enough directions to keep it fun and positive.
Maybe if you are a college grad with 0 real life experience then maybe interview prep is necessary... don't know. I could be biased though. The last place I interviewed at they knew who I was, something about my software, and some of my online controversies before I even walked in the door.
The best preparation for interviewing at large companies is having a second part-time job somewhere in management. I held my first management position in a part-time job at age 24 and was once a director. I have never held a management position in the primary full-time career, which is a weird inverse of power-distance in some work meetings. Being a parent is also good experience for dealing with people.
What they need to provide education on isn't dominating the interview process... but drilling down on the proper information necessary for new candidate retention.
I have worked at places that are awesome and really work hard to ensure you are happy and constantly engaged in the work. I have also worked at places that completely suck full of benchwarmers with a million layers of abstractions so that code monkeys can feel a bit more confident. It is helpful to know if you are going to be miserable in the organization.
The candidate really does share some of the burden of figuring out if they will be a good fit for the organization, but this is often really hard to interrogate out of the interviewers even for experienced people.