The arguemnt low mileage runners use against high mileage runners is:
"Running less lets you do harder workouts and makes it easier to recover and stay healthy"
Which, technically, is true. But that's not the point of high mileage. High mileage runners aren't just running more miles but doing no quality. To do it correctly, you need to do both. In the long term, the higher mileage runner would be able to get in better quality workouts, too, because they are more used to running than the low mileage runner and have better trained their bodies to recover from the workloads. You run more in base to be able to handle the hard quality work during racing season.
Example:
I got to consistent 70mpw the summer before senior year of college because I knew I had good natural speed and I wanted to be a better miler. 70mpw was a lot more than the 50-55mpw I did the years prior. Once XC season came a long, I lowered the mileage to 50-60 and did the workouts and I was fine. Better than ever, actually. Then track season came a long and I upped my mileage early in winter again before getting into workouts. My mileage ended up really dropping without me really realizing it. I was just doing the hard workouts and getting in the easy mileage in between so I could recover. I dropped to 40mpw during the majority of february to May as I trained for the 800m and put in a LOT of quality work. Without that base I built over XC season, there is no way I would have been able to sustain the kind of training that led me to my breakthroughs from 400m-5k I had that year. If I was training for 5k I would have liked to keep my mileage higher, but again, the base was there and that was the most important thing. You need both the miles and the quality to be at your best. They compliment each other. They aren't enemies and there shouldn't really be a "low mileage" vs "High mileage" approach. You should run as much as you can while still getting in the needed quality. Then after season, reset and try to build a little higher. Etc etc until you find your sweet spot, which really shouldn't be lower than 60mpw if you want to be your best, but ideally might be as high as 90-100mpw, depending on event and experience.