Aluminium has no place in a drivetrain if you ask me.
Not totally sure I agree, I think it comes down to the intended use for the bike, the weight saving of Al Vs it’s wear rate is the debate really.
(carbon) Steel will still rust of course and that still needs to be managed or it can lead to future issues for with the wear and degradation of other parts within the drivetrain, same as with a chain or cassette.
But I’ve not found Aluminium rings to be a huge problem, it’s more the conditions and frequency they’re used under that causes issues;
I’ve recently had to retire a Superstar N/W ring from my gravel bike after it finally developed a bit of a ‘hook’ to the teeth, that was after about 2700 miles and a few chains, that seemed reasonable to me on a bike that’s been ridden in all weathers and types of muck, the Aluminium Stronglight rings on my road bike are approaching 6000 miles old and show no real signs of needing replacement, I reckon they’ll make 10,0000 miles without issue.
MTBs do tend to have smaller chain rings and thus load is shared over fewer teeth normally, with extra moisture and abrasives added, I think a better justification is there for a steel ring if your running 1x with a 32t or smaller and chasing longer life on a bike used year round, but being honest about it, these days my MTBs (both with dinky N/W rings) don’t really do the annual mileage to justify changing to a more durable Steel/Stainless Steel ring these days, If I was getting less that 2 years out Al rings them I’d consider swapping to steel but that’s not the case.
I suppose the only other question specific to DM rings is the interface between the ring and the crank, can a steel ring chew that spline pattern where an Al’ Ring might be the sacrificial item in the interface if something has to be, has anyone observed an issue with this or is it just hypothetical?