There was an article that I read before that 97% of day traders lose their money on their first experience and the other 3% earns as much as a bank teller.
Though that may be the case, there are special exceptions to this rule. Remember that trading is all about experience. There are multiple factors in order to know the signs in which may give you an idea whether to invest in a certain cryptocurrency or not.
Going back to the discussion, trading is somehow a difficult job to be consistent with. There are others who found success in trading but there are lots of people who have experienced otherwise. At the end of the day, it really depends on how you view trading as a whole since saying that such is "not a lifetime job" invalidates the efforts of others who have made this their careers in their lives.
Lifetime job, in my opinion, presupposes a person’s self-identification with a specific type of activity. Defining onerself through one`s profession. I believe that modern realities go beyond this definition, because people have to expand their skills and master something new in order to remain in demand and competitive. A person can consider himself a trader. But this does not mean that he will not have to master other types of activities throughout his life.
I only understood the last sentence you said- anyway, I do agree that a person may venture into other types of jobs whatever they want to. Generally, people trade cryptocurrencies and they view it as a sideline to their main job. While I do agree to a certain extent to what OP said, still, there is a handful of people who found success in trading and saying what OP said invalidates this fact.