Yes, but that's not why raidz1/raid5 is "dead" on spinning media. That issue is due to rising URE rates going along with larger drives and longer re-silver times. Otherwise, raidz1/raid5 would have always been a poor choice. I mean, you're always in a degraded state until you fix what went wrong. Even with a hot spare (which freenas doesn't support if I understand correctly), you're unprotected until the resilver process completes.