Advice I got from a lawyer friend is that getting out of jury is very easy - just ignore the summons entirely and nothing will happen.
You correct that they won't accept any excuse but the system mails summons more or less at random and so the summonses go to many non-existent persons. Moreover, a letter isn't legally binding by itself - you can always say you never got it but since they get to so non-shows, the system never bothers to hunt-down those who never show.
About 25 years ago, I read about a sheriff simply rounding up an elevator full of persons at a county building when the jury pool was low. That is an exceptional case, but I believe that jurisdictions vary in how hard they chase no-shows.
You correct that they won't accept any excuse but the system mails summons more or less at random and so the summonses go to many non-existent persons. Moreover, a letter isn't legally binding by itself - you can always say you never got it but since they get to so non-shows, the system never bothers to hunt-down those who never show.