- Unsupervised learning techniques, e.g. transformers and diffusion models. You need unsupervised techniques in order to utilize enough data. There have been other unsupervised techniques in the past, e.g. GANs, but they don't work as well.
- Massive amounts of training data.
- The belief that training these models will produce something valuable. It costs between hundreds of thousands to millions of dollars to train these models. The people doing the training need to believe they're going to get something interesting out at the end. More and more people and teams are starting to see training a large model as something worth pursuing.
- Better GPUs, which enables training larger models.
- Honestly the fall of crypto probably also contributed, because miners were eating a lot of GPU time.