Certainly possible that the Church is failing in both. However, it is logically and rationally improper to link the two as they have distinct different factors that affect “success” or “failure”.
The failure of a wedding to be a sacramental union is rooted in the failings of one or both of the individuals at the time of the wedding. They are the primary active participants while the Church is a more passive participant.
The failure of a tribunal to properly grant or deny a request for an annullment is rooted in the failure of the clergy involved in the process. In this case, the couple are the passive participants while the Church is the active participant.
A comparable analogy (not perfect) would be I give my blessing to my adult daughter’s decision to get married. The marriage fails because her husband intractably continues to abuse her and her children. While I might have failed her by not doing my part in properly preparing her for spouse selection, it doesn’t change that it is not a good thing that they continue to be subjected to the abuse.
The difference between me and the Church is that I am not empowered to determine whether the elements of a sacramental union existed or not. This is a charism given to the Church and I’m called to accept their decision. Either way, I’m called to assist my daughter and grandchildren from the abuse.
P.S. For clarification lest my daughter read this and she think people might think something is amiss in her marriage, this is a fictional analogy and in no way reflects reality. I love you Kitten and your hubby!