[jaclaz]

I don't really know the specifics on this artist's success/income, but investing has the pre-requisite of being able to save the money first.

Generally speaking, and of course with all due exceptions, most painters, even many of those that were later acclaimed as masters, tend to have the need to sell their artwork in order to barely survive, so, besides the missing online brokerage, there would be the issue about the possibility of saving and investing.

Anyway, to provide another easy comparison, the Average Hourly Wage[1] in US in 1970 was around 3.50 US$, while now it is around 22.50 US$, assuming that buying power is correspondent, the US$ 1,500 in 1970 represent something like US$ 10,000, IMHO not that bad for three paintings.

[1] Series Id: CES0500000008 here: https://data.bls.gov/timeseries/CES0500000008