[wpietri]

You can't just make up new meanings for words. Speculation is a defined thing in the financial world: https://en.wikipedia.org/wiki/Speculation

Investing in art happens all the time. Movie companies do it reliably when they create or purchase films with the hope of generating both economic value (that is, enjoyment) and long-term profit. Music companies do it when they give a band money to make a new album. Touring art shows could also be seen as an investment where they acquire assets and then generate value (that is, viewership) with them. But yes, buying and storing paintings in hopes they will be worth more later is speculation.