This year though, nearly every blade of grass in full sun is now dead. I mean, dead. Crowns, roots, all fried. We've finally gotten rain, and all the neighbors lawns, which they mostly ignore, are lush. My lawn is brown and crunchy.

Now of course we're hearing that this past July was the hottest on record. So this year was unusual. Still, it irks me to see the rest of the street with green lawns, while mine, which I baby, is dead.

My lawn is too large to irrigate, have nearly 3/4 acre of just turf.

Anyone else seeing this happen?

As lawns go brown they go dormant....they are not dead...they are ..let's call it resting. when the cooler weather returns, and with some moisture, they will return their green lush growth if they have received sufficient energy in their roots to grow. I speak of fertilizer. If you have regularly fertilized with a nitrogen based food the lawn will return. If the lawn is depleted of nutrients, then it will have a slower return rate and may not perform up to your specs.
Fertilizing regularly with a nitrogen based food encourages those bare spots to come in from what grass is there.
Further encouragement can be given....but never, never, fertilize during a heat spell. If the lawn is not growing it cant use the food so don't waste your money.

Your neighbors evidently, either have a different grass type than you do, or they have taken the time to water that 1" per week which is the usual recommendation.
Lower amounts of moisture can cause the grass roots to grow shallow; subject then to heat and loss of moisture.
High amounts of moisture also can cause the same effect.
Thus those lawns on flood plains are often put at risk.
Too much of anything....even if its good, is too much and can cause problems.