re: How does someone get out of jury duty?

At least in Louisiana that is still not an excuse to not be in jury duty. It affects everyone that does it. It may not be "fair." But you and your wife aren't "special."

With a new Tundra and a year old bass boat and weekly excursions to the lake you shouldn't be hurt too bad by one week of your wife not bringing anything in. Unless you're living beyond your means.

Where I live, you can write a letter to request to be excused based on some type of hardship. Have her write a letter explaining that she is the family breadwinner and due to her self employment, it would cause a hardship for the family if she were to miss out on a full day or more worth of income.

ETA: just saw you said she's summoned for next week. You probably waited too long at this point to get excused for hardship.