I think manufacturers need to start looking at external and internal rim width independent from each other. The super wide Rovals are the only rims that really seem to do that. Sure, you can argue that making gravel rims as wide as a gravel tire provides aero benefits, just like with road rims. But you can't increase internal width infinitely alongside that. Especially in a discipline that requires the tire to flex and at least be able to somewhat squirm under load. Also, it unnecessarily exposes the rim's sidewall to impacts.
All this is less of an issue with road rims due to the much higher pressures and surface tension in a road tire. But with 42s at somewhere between 25-35psi you can't count on the tire to be that stiff. Plus we're talking offroad riding, rocks and sometimes roots. It's just asking for trouble. Which that review demonstrated very well.
My gravel rims are hookless and 25mm internally mated to 40mm tires. That's a great combo, but increasing inner width even more makes for a more and more exposed tire sidewall. If you're mainly riding asphalt and the occasionall silky smooth dirtroad, then no problem. But if you're looking for a go anywhere kind of setup, that's not a good idea.
