I would tend to agree, but it really depends on the capabilities of the AGI and how much more capable it is compared to previous models. If the AGI can do any sort of bootstrap, improving its own capabilities on its own (basically a fast takeoff), then all bets are off. An AGI that achieves superhuman intelligence can surely make money in a lot of ways; not only by playing the markets. There's a whole host of ways of making money online these days, and also remember that such an AGI would probably be capable of generating convincing speech and video, meaning that it could act as a person (or rather, a whole host of persons, both stealing real peoples identities by cloning their voice and face, and also making up fake ones).

However, in the first place it seems highly unlikely that an individual would arrive at AGI before major companies or governments, because of the hardware requirements alone. Not too many individuals can spend millions of dollars on compute for training a large model, which seems to be needed.