Both United and American allow 8 companions for platinum/1k and executive pro/platinum.

I feel the difference is too big. I mean, what if you have a family with 2 adults and 2 kids.... ? If Diamond can only auto-upgrade one companion to Comfort+, while United/AA can allow pretty much the entire family to Econ+ / MCE, why would Delta's loyalty program be better than AA/UA's?

I wonder why Delta is so stingy in this regard for its top loyalty member?