People forget how hard the Outfit got hit in the 1980's and 1990's.
The Outfit has, in my opinion, been a minor-league operation since GAMBAT, Strawman, and their substantial removal from labor unions. These three things turned the Outfit from a powerhouse to just another street operation, for the most part. They've never recovered and they never will.
As for the actual members themselves, the Outfit started using the ceremony later on and seems to be much more careful about who they let in. They're more about keeping a smaller core and a low profile than keeping a certain membership quota. It makes for short term quality but can hurt long term viability in terms of general attrition.
Now this is an excellent point. People are always going on about how the Outfit lets in very few members and is oh so discriminating and selective but... has there ever been anything else in the past that was a better way of ensuring the final destruction of a crime family? If you've got a family down to a handful of capable guys, this might superficially seem like effective streamlining, but what happens if one of them flips? Everyone in the family who matters gets RICOed, and the family is toast. The only real demonstrable effect of mob family streamlining/downsizing/exclusiveness is this: it makes it possible to cram the entire family into a singe RICO case.
Cleveland and Pittsburgh, for example. Scalish and Mike Genovese refused to make people; they kept the families small. This might have benefited them personally in terms of moneymaking and insulation (both died old, free and rich), but as soon as one of the core guys flipped (Lonardo in Cleveland, Porter/Strollo in Pittsburgh), the families were destroyed. I think downsizing is a seriously bad idea if the mobsters want "the tradition" to continue. But I seriously doubt that the rich ones care about that silliness as much as mob message board posters.