Having been in the SSPX formerly, I can tell you that their growth was more rapid in their earlier years. From about the mid-90's on, that growth has stagnated as you indicated. Their only growth is now coming from large numbers of children born to its members, and a sizeable percentage of these children have not nor will not necessarily remain either in the SSPX or as practicing Catholics. Sad, but the same overly authoritarian attitudes of pre-V2 are rampant in the SSPX, and those attitudes are having a similar affect on how the children cannot embrace Catholicism personally and lovingly.
I am glad you have found an Indult community because we all need the support of others. I appreciate your candid observations about the sspx. I know that prolly wasn't easy to admit as I am sure you still have friends within the group.