This is a great discussion, with a lot of good responses.
Without being an authority on the subject, my impression is that people who become wealthy tend to want to create something that will live on after their death that they’ll be remembered for. What that thing is is likely influenced by societal opinions of the time and the individual person’s interests and passions.
Art has long been one of the things that lives on after someone has died, but with the industrial revolution in the 1800s, industry and automation became another avenue for people to make a lasting legacy. Combine that with the tendency for people who are successful in current technology endeavors to be less adept or interested at personal expression, it’s not surprising that they would lean towards more practical legacies.
It’s not 100% though. Bill Gates, for instance, donates a lot to the arts, even though his pet projects are things like eradicating malaria.