I think the “unlock” is that AI firms were given trillions of dollars to discover new techniques. In fact, there are very few industries where a sudden influx of that much money would not lead to rapid advancements. It’s not really unique to the AI field.
Your timeline is a bit backwards: they were given trillions of dollars only after they'd demonstrated a few pretty remarkable advancements.
The fact that their advancement suggested that pouring more compute would continue working was also especially attractive to investors: it made a massive R&D budget feel like less of a risk.
