I ran my 10K pr on low volume high intensity. I was very very fast and sharp at the time. 5:20 pace felt like a jog. That opposed to very high volume when 5:20 pace is working hard. I've never run within 30 seconds of my PR in the 10K when training high volume.
I should also note I ran a very good (for me) half marathon pr on 5K training. Once again I was fast, but didn't necessarily have super great endurance. 5:40 pace was pedestrian so it was easy.
Of course maybe I just haven't had the right day. I've just never felt quite as race sharp no matter what type of taper off of higher volume training. Yes I understand all things equal high mileage is better. I've just never been able to quite put it together when it matters.