For the majority of history that's been the norm. Only in more recent times, with the advent of widespread tertiary education people are more likely to choose their own path as opposed to going into the family business.

Back then, pretty much everyone had. If your dad is a shit shoveler, then you're also a shit shoveler. Cause unless you find someone else to let you be their apprentice, your parents are the only ones who are gonna pass on any knowledge of a trade. Plus, your dad already got the shovel and the cart, and that's an investment!

A better question, more in line with the logic of the meme, in the modern age would be "of those people whos parents own wildly successful businesses, how many of you work in the family firm?"

1. I'm not fuckin' legally bound to a profession because of my ethnicity or religion.

2. Grandfather was a factory worker. Mother was a factory worker. I'm a clerical worker.

3. As anyone with a parent in a specialized trade can tell you, having connections and a ready educator is a huge advantage in getting into that trade.

4. Banking requires capital. Guess what families tend to pass down?

5. Family businesses, and professions, were MUCH more important in the pre-modern age.

How many of you have the same job that your parents have?

Yes, Mister Smith, can you imagine having the same job as your parents? Mrs. Baker and Mr. Clark come see this fool who thinks that jobs were passed down in families. Mr. Cooper, you're not going to want to miss this either. Same with you Ms. Parker and Mr. Bailey. Mr. Chapman, Miss Hunter and Mr. Knight too, you won't want to miss this.