I believe it is fair to say that there are proportionally many more divorces among those that dated their spouse in the 10 month range than among those that had in the range of about 4 dates prior to engagement.
Yes, but to attribute that to the dating process is overly simplistic. It is much more likely that it is due to societal norms in the communities which do each type of dating.
The relevant question is whether the communities that currently do one, would have less divorces if they would switch to the other.
Otherwise, you are just arguing that they should switch their whole community culture.