Well to be fair those training exercises are probably done in near ideal conditions of altitude, landing zone, forward airspeed, and you know it's coming have studied mentally ahead of time. It's one thing to pull it off during training and another when the engine fails at a random point during a flight in LA/SF/NYC.

Don't you think pilots would tend to try and stay within that "safe autorotation" envelope most of the time while flying? It seems mostly a case of having sufficient altitude and/or speed, similar to what fixed wing pilots try and maintain - a safety margin.

Why would they?

They will probably want to fly across non easy terrain because otherwise you could just use some other means than an expensive helicopter.

Hight perhaps but you will fly across water, woods, power lines, cities.

Watch a helicopter take off sometime. It (almost) never lifts into a hover and climbs straight up. Instead, it lifts slightly off the ground and accelerates forward following the recommended takeoff profile.

That’s so the craft can stay in the “autorotation possible” section of the HV diagram as much as possible.