What they believe is that "AI iS tHe FuTuRe!!" and that chatbots will replace all the plebs and somehow they will get richer off this, rather than get hanged by a starving, unemployed mob. There is no rationality in it; it's vapid suits believing ridiculous things while having cartoonish green dollar signs in their eyes. They can fund this nonsense because they have hundreds of billions of VC dollars to throw at a wall with absolutely no accountability. The reason they have that money, in a very small nutshell, is that interest rates are way too low and it's illegal for poor people to invest anywhere except the stock market.