The obvious reason is that they think it will pay off in the future. Google didn't start profitable, it is now one of the most profitable companies in the world

The obvious reason is that they think it will pay off in the future. Google didn't start profitable, it is now one of the most profitable companies in the world. Those who invest in money-losing AI believe that it will be the next Google and that profits will come. Or alternatively, they hope to sell to the greater fool.