> they are an extreme net good for the ecosystem.

Evidence?

Perhaps depends on what you mean with "ecosystem". Within the AI tech/hype, sure, there it's good. But for the economy as a whole? Is it that good? There are probably some benefits, but do they match the current valuations?

Most likely they don't, because hype cycles inherently overvaluate things for a while because they don't know what will stick. If things were not dramatically overvalued right now then investors would not be acting in their best interest.