As Mr. Adler was also saying, these general AI systems are done quite differently from normal software. In normal software, I would just write some lines of code on my computer. I'm a human, I write those lines of code, and I can understand what I am writing. Instead, these AI systems are not really fully written by humans. They are more grown rather than built. Humans write some lines of code to start the training process, and then, after sometimes multiple months and tens of thousands of supercomputers being used to train them, something comes out at the other end that is very competent but that we don't fully understand.
Your question was about why these companies are targeting these very powerful systems despite the risks. I cannot speak for the internal motivations of people, and I also don't think this should be our focus, but naturally, the stated goal of all these companies is to make AI systems that can replace all humans at all tasks. This doesn't just have an obvious economic impact, which is to make humans obsolete; it also gives power. It gives power over the economy, over governments and over the entire planet to AI systems that are fully autonomous and that we cannot control.
Some of them might do it for power, some of them might do it for short-term gain and some of them might do it for some misguided ideology of preferring AI to humans, but ultimately this is a very dangerous undertaking. The best way to deal with this is to ban these technologies.