How many such people do you know of personally?
Those people are callede Financial Advisers,
in many cases they are called Brokers.
Actually, they are not as rare as one might think. Many are retired, and investing is their retirement activity, often a passionate one. These are not necessarily public or high profile people, but there are a lot of them. Managing for others usually involves family members or very close friends; I manage 3 such accounts. I would not do so for outsiders. I do mentor a couple of young people who are learning, but I do not handle their money or make their decisions.
Some wealthy families can live off their money. They hire financial advisors to manage their wealth. Others are day traders. These folks have made a good chunk of money at one point and actively trade their own account in hopes of turning a good profit for the year. Both "invest without "working,"" but in entirely different ways.
Yes, many rich people are invest own money in their business. In London most of the families have own business, there is no need to others.
Lots. Some ull time private investors proabably have other interests as well that doesn't take up too much time. Like property investment/landlords
Are they rare? Yes. All rich families have what are termed "family offices" that invest their own money. In North America, there are probably tens of thousands of such families.
As in people whose only job is investing their own money or others' money, and do not have any other day job.
How many such people do you know of personally?