Ask HN: How will Artificial General Intelligence be invented?

I am curious to learn IF (and a big if) an artificial general intelligence will be invented, what will be the roadmap for such an invention? e.g. what would need to be created / demo-ed along the way to ascertain that such an invention might be possible? First it was chess, then image-classification, then Go...maybe a natural language demo will blow our minds soon...what would be the "next demo" (or a set of demos) that would show that such a goal is increasingly within reach?

Sub-questions:

1) There are some groups (e.g. Strong AI group in Berkeley, OpenAI, DeepMind etc) that are working towards the explicit goal of inventing artificial general intelligence. If a group has to start working on it today, what would be the approach that group can/should take? Is it possible to open a new line of inquiry that will add to this research?

2) IF (and again, big IF) something resembling AGI would be invented, would it be in large companies (with lot of data and compute power) or can a smaller group (e.g. a startup) approach such a lofty (and nebulous goal)?

Does HN have any thoughts on this?