I wouldn't say there's no correlation? There appears a fairly obvious line running diagonally from bottom left to top right, i.e. generally speaking the more tackles you miss the more points you concede (what you would expect).
But there are obvious outliers like Tigers, Panthers, Bulldogs, Knights which shows that missed tackles aren't the only driver of points conceded.
NRL showed an interesting video in an article yesterday about Maloney's missed tackles. He's up to 75 missed which is atrocious (next closest is Rochow with 51, Mitch Moses has 47), but they note that many of those MTs are a result of making decent body contact and stopping momentum, but without wrapping up the tackle, which counts against Maloney. His team-mates finish the tackle off. When they looks at the stats of missed tackles v line breaks, it turns out that Cooper Cronk is the worst in the competition.
Similarly there's Milky's argument that MTs impact attack, but there are teams that don't follow that either. E.g. Penrith high MTs but 4th-best attack in the league; Warriors have 7th best attack.
What I personally find interesting, and if this is a graph done privately, congrats to OP because I love it, but I find interesting the clustering of this statistic. A lot of teams lie on the average line - Saints, Storm, Roosters, Rabbits, Warriors, Cows, Titans - about half the comp, which you might expect. Sharks, Raiders Manly not far off this trend either, so probably 11/16 teams sit on the trendline.
However there are two interesting clusters - the low MT / higher points bottom left (Saints, Sharks, Melb, Dogs) and average MT / high points top middle (Broncos, Eels, Knights, Raiders, Manly).
What this appears to say is teams with very low missed tackles still concede a fair number of points per set, i.e. there is a sort of minimum points you will concede even if you defend well. This makes sense, and Dogs are the outlier because they don't miss many tackles, yet concede a lot of points. I wonder here if penalty goals are a factor, i.e. points conceded without missing a tackle. Or another possibility is that Dogs don't miss many tackles, but when they do, the opposition is a high chance of scoring points.
The second cluster is the more interesting to me. It indicates that there's a real sweet-spot in terms of conceding missed tackles and points; that if you have a low-to-average number of MTs, you can still concede a lot of points. You'll note that probably 7-8 teams site above the trendline, i.e. more towards conceding points, and again this is probably an indicator of the fact that football teams generally concede a standard # of points per game, no matter how good their defence is (between 8-20 points on average).
But you'll note that Tigers and Panthers appear less worried about MTs, that they are prepared to concede a lot of MTs and still defend the line. There's probably a trend for these teams of conceding MTs in mid-field play rather than in the defending 20\. But for those teams in cluster 2, they have average of better MTs, yet conceded high points. Perhaps if those teams focused less on MTs and more on swarm / cover defence, they'd concede less points?
