There are much simpler games with a 'pay for content' or even 'pay for progress' mechanics that probably make more money than BG3. Unfortunately I don't think big, high quality games like BG3 is where the biggest money is. Purely guesswork of course since I don't know the numbers. I think the motivation for making these games comes from something else than just making money, although getting return on the investment is a condition of course.
All in all: The success of BG3 may encourage game companies to invest in more such games, but it will not be the only factor.
