... netting that is held together with metal hoops, through which you're shooting at high speeds.

If that situation occurs for which the netting is there, it follows that the riders are hitting those hoops at full speed at an oblique angle. You're not going to somehow nicely land between those metal hoops and be caught just by the netting alone. (If that were possible, it doesn't seem safe, either, for that matter).

A much more appropriate restraint (if we can even discuss such a thing here) would be for that section of the track to be a fully enclosed, smooth tube.

Yes NASCAR and IndyCar oval tracks have catch fences around a at least part of the tracks. These are for the safety of the fans, not the drivers. Crashing into the fence will shred the car. This is how Dan Wheldon died.

Not to mention that both series design cars to avoid going airborne or rolling as much as possible (the fenders on the DW12 IndyCars, the arrestor flaps on stock car roofs).

Alternative would be a different track layout. Universal opened Volcano Bay last year with an aqua coaster where it's pretty much impossible for the raft to come up because it, surprise, uses upstops to prevent it from going airborne.

Whats interesting, and where they probably for the idea for the netting (they have one in the park): https://www.whitewaterwest.com/products/master-blaster/

The difference, of course, is that the netting in the image on that page pretty obviously isn't meant to catch people. It's more likely there to keep birds out or to keep somebody's phone or hat from shooting across the park at high speeds, or just to keep idiots from intentionally climbing out of the tube while it's elevated.

It is pretty normal to have netting underneath things like inverted rollercoasters, since people inevitably drop things... Not netting where people could collide with it.