That's very fair, I'd want to know percentages before signing up too. Personally my family learned "TIP is legit" through word of mouth as well as through FAI's public Facebook group (
https://www.facebook.com/groups/885290875293805/) which is super helpful for getting the scoop from families-- good and bad.
The family that introduced us to TIP had struggled with OIT. Fwiw TIP claims 99% success rate versus OIT's ~80%, but I understand this is the very contention point being discussed here. FAI does report TIP statistics (https://public.domo.com/embed/pages/X6NX5). Anecdotally from my 6 years as an (adult) patient at FAI, the "99% success rate" seems entirely plausible to me; it is very rare to hear of complications -- for example almost nobody on the internet makes posts about negative TIP reactions because everyones experience is indeed overwhelmingly positive.
However, none of this dismisses it's a huge bummer FAI isn't getting TIP clinically proven right now -- it'd be a much easier sell to prospective families than needing them to chat with other parents on Facebook about how really legit it is.
Deciding to not trust TIP is also totally fair. Everyones journey with food allergies are different. Completing TIP also takes an extraordinary amount of personal sacrifice too (I for one took a gap year away from school to finish). But as another food-allergic who's scientifically minded and initially thought "where's the research to back this up" too before enlisting, I feel almost obligated to share my story.