So any time there's a crash now, we're going to ground the worldwide fleet of that model of aircraft until we have a final report on the cause?

If it happens to a brand new plane? I'd say: Yes; that's reasonable.

At least until the cause is known.

Edit : Some clarification

Cause is always complicated in an air crash. We don't officially know the cause of either of these crashes.

When MCAS was established to be a likely factor in the first crash, Boeing issued an emergency airworthiness directive to all operators of the 737 Max, alerting pilots to the possibility of undesired nose down trim, and reminding them that the runaway trim procedure would disable it.

Which was far from enough as we can see. Full retraining and perhaps other actions should have happened immediately so Boeing could hold any form of moral high ground here.

When it comes to mass transport, safety should definitely have higher priority than pushing some potentially new cool tech ASAP (which is debatable, making plane unstable ain't cool by any measure)

And they're still draging their feet on the retraining issue.

No simulator time required, no sire!