It's an efficiency problem, our brain work on 1/100000000 the energy required by a data center at a 1/100000 the size, it should tell you how efficient brains are.
You can throw resources at it but you'll be limited by bandwidth.
But the fundamental problem is that we don't know how consciousness works. And if the goal is to reach AGI, at what scope? Have it create new technology? Wouldn't those billions have been better invested in research teams?