Training is overrated!

Some people on RWOL joke about this statement when it comes to racing long distance. In my case, there is a lot of truth to that statement. The last 3 months of training have been horrid. The truth hurts. Here are my mileage totals since August in reverse order:
17.5, 27.0, 50.o, 45.5, 10.0, 35.0, 45.0, 23.0, 30.0, 30.0, 20.0
That's an 11 week average of 30.3.
I wanted to average at least 45-50 during this period in preparation for a November half marathon. No way that I should expect to be in PR shape right? Wrong.
Trak Shak 5 today in a moving time of 33:14 on a gently rolling course. That beats my previous PR of 33:36 set in May, which was done just after marathon training. I was not exactly fresh either. Two days ago, I did a hard 5K tempo near race pace. I've done 17.5 miles in the past 3 days at an average pace of 7:30 (that's near half marathon race pace). Am I surprised? Not really. The greatest determinant to how I perform in my runs is not the volume and quality of my training but the degree of chemical imbalances in my body.
Back in college and grad school, due to injuries and lack of time to train, there were years in which I only averaged 10-15 MPW. I could still run a 5K around 21 on a good day and was sometimes faster in all out time trials. When I am far enough out of balance to produce symptoms, I will not even come close to a 21:00 5K even if I trained at 60 MPW on a consistent basis. A 10K would be really ugly and anything longer than that? I'd have to walk/jog to the finish.
Now, is it too much to ask for me to have a few months of solid training that is relatively free from setbacks and interruptions? Every time I hit a good stretch, I am hopeful that I've got this disease beat once and for all. Then, a few days later, I hit the wall after 2-3 miles. This time, let's just say that I am cautiously optimistic. With solid training at even 50 MPW, I expect that by the winter, I will be well under 3:30 in the marathon and improve my PRs significantly in the shorter distances. I know it's wrong to compare myself to others and I should just continue to focus on doing the best I can with my own life but I sometimes get dejected when I see other bloggers consistently post 70+ mile weeks and they consider it a downer if they don't hit 80!