Highly variable on the athlete. For most guys, 100mpw is a good standard to shoot for, but some might not be able to handle that much. Even Lydiard said if you can run more than 100mpw, don't, just run faster. Most marathoners these days are going 120+mpw at least part of the year, some go 150mpw much of the year.
I'm a big proponent of mileage even for 1500m runners (at least during a large portion of the year that does not include peak racing season), but guys like Cam Levins are the exception. Obviously it works for him, but most guys would not run well off of that kind of mileage. For a standard 5k college guy, I'd recommend 90-110mpw during base, and 85-105mpw during season, dropping some towards the end of the season. I had the best race of my life the season I upped my mileage to 100mpw. At first I didn't see much improvement over 80-90mpw, but the difference came when I started to taper for championship races.
The most I've done is 106mpw, but I've done 55 miles in three days before too (got sick that week and missed a day, then took a low mileage recovery day and ended up in the 90s). If you build up slowly and have a few years of training under you you can run quite a bit. More does not always mean better though.