This article did nothing to establish tortoise life span. It refuted a few possible hypothesis, but that's it. How is this relevant to subject at hand?Here's a study I found. I didn't read it cuz I really didn't want to lol. I believe it's on reptiles, not just tortoises.
Centenarian tortoises keep their secrets as longevity theories busted
lighthouse.mq.edu.au
This second article talks about many studies on several types of reptiles, but list no studies on how long tortoise live, no guesses on what their lifespan might be, and certainly no data on tortoise lifespans.Here is another https://www.the-scientist.com/how-slow-can-you-go-70163
I guess you just have to find the right wording to find the info looking for.
Take the info as you wish. No human can live long enough to do a 100% study. If they could, they would be helping humans live as long as you'd have to live to do the kind of 100% study some people want!
What was the point of posting these articles? They simply prove my original point that is: No one knows how long tortoises live. We know it is a long time, several decades at least, because we all know of many anecdotal examples that demonstrate this.