The preponderant bottleneck is inventing new architectures to make AI actually good at human and superhuman tasks. For example, AI agent harnesses add tool calls and long term state management, allowing AI to autonomously complete complex tasks. Once these are in place, finetuning models with examples of good tool calls helps, but somebody first needed to invent the fundamental capability. Now try to implement humanlike long term memory for AI to be your coworker or life assistant working on tasks that last month. Even if necessary low level technologies are already there, structuring them to be practically useful is non trivial.