What makes you think AGI means AI is a complete field? Wouldn't that mean working out how to build a bridge without trial and error completed engineering? Or that biology was completed when we worked out how dna works + enough organic chemistry? Obviously we won't complete the field in our lifetime, but that's because nothing is ever really complete.

I think I'd put the chances of AGI within my lifetime at 30%. Low, but high enough it's worth thinking about and probably worth dumping money into.