There are many reasons. 1. There were better opportunities for Italians growing up in the later years. 2. With the pool of recruits shrinking decade by decade, there was no need for big ceremonies just a guy or two here to make sure the money flow kept coming in. 3. With many bosses and administration members getting arrested and convicted in other families, they felt a small group would attract less attention and were not into many things so they could be in a loop of what activities they were doing and not being blindsided by what a soldier or capo was doing that tracked back to the boss only from collecting their cut. 4. Many of those mobsters had good sources of legitimate income and were getting up there in years, so they partaked little and little over time until they felt it was time for them to retire. An opening opens up but not really anyone who was qualified to be made, just low level idiots or knuckle heads. 5. Through family ties they had quality members who only served as associate who kept a minimal distance just in case a RICO charge came down, and thus would only he detained through suspected activity, but would not damage the crime families income from that valuable business.