Daniels 2Q lower mileage plans - very little mileage on E days

4-5 miles on easy days sounds about right for 50 miles per week. An important aspect of good training is "blocking", which is clustering training stimulus into a single day, followed by a couple days of recovery. For example, 16-mile day with a big workout followed by a 4-mile recovery day will be a better stimulus on the body than two 10-mile days, both of which contain a moderate amount of hard running. It will also be easier on your body. Daniels I think discusses this is in some editions of TRF. Joe Rubio talks about it in his middle distance guide. It's also one of the foundational principles for the Norwegian method of double T.

If it makes you feel better, my easy days are only ~10 miles for 90-100 mile weeks. I don't follow Daniels 2Q, but that's basically the same ratio of easy day mileage to total mileage.