Comment by jsjohnst

Sure, it’s had no fatal accidents (but six hull losses), but few were built (377 total) and only a third are still in service.

Even assuming all of those were in service the entire 27 years since launch (they weren’t, as most weren’t built till part way into the production lifetime) and assuming they were flying 24x7 over that duration (which they weren’t), it would still be less than 10% of the flight hours of the 737NG alone. Even by wide body, four engine standards, it just wasn’t a highly flown bird.