The very page you describe specifically states that you can't infer when failures to deliver occurred because the data is reported in aggregate with no age statistics. [1]
Moreover failures to deliver can occur on both the long and short side, and do not necessarily represent that a naked short sale occurred. [2] And when they are associated with a naked short sale, it may still be legitimate. Market makers are legally allowed to engage in naked short sales to facilitate liquidity, and if they can't fulfill the borrow in time (which would itself happen for legitimate reasons), that failure to deliver would also be reported.
Finally - reporting an increase in apparent naked sales to the SEC by gesturing towards data on the SEC website doesn't make sense. The SEC is definitionally aware of it. There may not be an active investigation, but these kinds of datapulls are pretty manual and staffed by people familiar with the data.
> since 1992, there had been six investigations of Madoff by the SEC, which were botched either through incompetent staff work or by neglecting allegations of financial experts and whistle-blowers
If what’s going on is naked short selling by those who are not market makers then it’s illegal and those who are doing it need to be prosecuted.
If what’s going on is due to a lack of liquidity then it suggest that price manipulation could be occurring in the form of excessive coordinated short selling.
Finally - why assume a government agency is competent and has the means and resources required to act in a timely manner? The issue was reported though. [0]
[0] https://www.reddit.com/r/wallstreetbets/comments/kr98ym/gme_...
That's not the assumption.
The assumption is that facts manually assembled and reported by a government agency are already within the knowledge of that agency, so even if they don't have “the means and resources required to act in a timely manner”, you aren't helping by reporting those facts back to them.
(This may also be an unwarranted assumption , but it's a different assumption than you describe. I've definitely in the past—on behalf of a different government agency—frequently been involved in reporting facts assembled by one office of a government agency to the parties responsible for acting on that information in another office of the same agency who hadn't been informed of it.)