So suppose that likewise, the risk of a fatal accident on Allegiant is 10 times as high as their peers. How dangerous is that really?
The good news is we don't have to suppose. We have actual data....many years worth.
If the risk of a fatal accident on G4 is 10x higher than DL/NW, and if DL/NW fly 10x as many passengers as G4, then G4 should kill 100x more passengers than DL/NW over the long haul. Assuming, of course, that doclightning's "calculations" are correct.
According to the actual data, DL/NW have killed 321 people since 1987. So if doclightning's calculations are correct, G4 should have killed 32,100 people in that time frame. Since the actual number is 0, not 32,100, it is clear that doclightning's calculation is completely wrong.
You multiplied when you should have divided, in addition to counting 10 years before Allegiant existed.
And Doc's calculation wasn't crashes. It was the lesser category of incidents. As I suggested, you can go to the Aviation Herald and see that Allegiant comes up quite regularly despite being far smaller than most of their peers.
Most importantly, you and others are conflating what other airlines did wrong to cause crashes in the past with what they're doing wrong now.
In the theme of the "captain obvious" comment that "every passenger of an airline survives until one doesn't," I remember frequent commentary when I was growing up about how the Concorde had the best safety record of any passenger aircraft. And then suddenly, it had the worst safety record of any passenger aircraft, with 8% of planes in service having been involved in deadly crashes.
In the aftermath, it came out that there had been numerous prior incidents of serious damage caused by blowouts, including fuel tank punctures, hydraulic system damage, and engine damage. But none had ever crashed, so the problems were never meaningfully addressed, and eventually the problems did cause a crash. This kind of "normalization of deviance" was also highlighted as a factor leading to the space shuttle Challenger disaster - risks were not being addressed because no serious harm had previously happened.
So yes, Delta has had many more crashes in the past than Allegiant, but to make another captain obvious statement, a past airplane crash can't kill a future passenger. The real question is who is currently doing a better job of preventing a future crash? That's not an easy question, and the FAA is in a better position to answer it than you or I, nor is any airline absolutely perfect in this regards, but if Allegiant is actually having more reliability issues and occasionally turns up planes with flight control surfaces not properly attached to their actuators, it tends to suggest they're doing a worse job.
As I pointed out before, it seems that even on Allegiant you're pretty safe compared to other common activities like driving. I can't make a strong argument for avoiding them based on safety alone (although I also don't hear much flattering about their comfort, timeliness, or service). If some people want to do so, that's their choice, and incidents like the runaway elevator merit stern criticism, but also please don't exaggerate the risk.
That doesn't mean they don't have to make changes. If the FAA finds they are deviating from the safety standards, the lack of past crashes doesn't justify them.