Every year from the beginning (3rd year) there is a section of the lawn
that is naturally brownish, weedy and thin with the other parts of the
lawn respectable. Ironically, my "fantasy" of a perfect lawn exists
right up against this "crappy" section....imagine this 3 acres of lawn:
most = respectable; 1 section = crappy; 1 section = "perfect"...of
course this "perfect" section is right up against the bad (weird).

Anyways....when I go to Lowes and come back with my fertilizer (gets
expensive for 3 acres) after about a week the entire lawn looks great
including the "crappy" section then about 6 weeks later I'm back to:
good, bad, perfect and the cycle begins again. This cycle has lasted 3
years.

Question: How does a person make their lawn permanently "good" instead
of going through the cycles of using fertilizer? I know it's possible
somehow since I have that one really good section and most of my lawn
is respectable without using any fertilizer.

Of course the answer might be: what the heck is the difference between
that: "perfect" section compared to that "crappy" section!

Both sections in full sun, relatively flat and same seed...for that
matter my whole yard is this situation.

My only thought (doesn't sound like fun) is to kill all the grass in
the "crappy" section; till it up, shovel up some "top" soil (if that's
what is), dump it by the railroad tracks , and bring in some new top
soil from somewhere that looks "good", finally reseed.