Mayan1, there are many who do this already. Their marriage rate is not higher than those who exclusively meet through a shadchan (it’s probably lower), so there’s no reason to think it would help.
In fact, it’s interesting to observe that the more a group is restrictive in its “dating” process, the higher the marriage rate seems to be, moving up successively from secular to MO to yeshivish to chassidish.
This in no way proves cause and effect, but it certainly puts some doubt into any theory which proposes loosening restrictions as a means of increasing marriages.