Mile time trial

Well the weather is great! Hot!! Breezy! Sunny!! Couldn't be better. I found the track in Ozark and had it all to myself. I did a two mile warm-up with some pickups. I was thinking of my strategy for running the mile time trial. All out! Sad fact: I'm so much slower than I used to be!
The first lap was in 1:39.06, I felt pretty good but definitely out of my element. This was all out, lap two was tragically slower, I even thought about quitting! A 1:47.24, or 3:26.30 half. I really bit the dust on this third lap. I mean to tell you I'd not run this hard for years! Pace really slowed and I really wanted to quit! A 1:53.69. I was trying to recover a little and maintain. I so wanted to break 7 minutes. A 1:52.40 fourth lap, and friends I was sucking air like I'd just come up from the bottom of the ocean; finishing with a 7:12.35 all out mile.
What's this tell me? I'm slow! Interesting, the Garmin said I did the mile in 6:59, but the stopwatch doesn't lie! I also think this is a very accurate assessment of my current ability.
This tells me, I don't quit. The mile is a tough race, too. I am now mulling over an additional element of marathon training. If you improve your mile time how will that translate into longer distances? What if I trained specific to improve the mile time during the course of marathon training? Here's an example of what I'm thinking.
Week one track workout-like today- 2 mile warm-up all out mile-2 mile cool down. each week increase the all out segment by 400 meters but make sure the first mile is 90-95%.
Think about it....what would happen?