> The ideal team size now appears to be 2-3 engineers per project

That's pretty much always been true for greenfield that doesn't require large swaths of boilerplate (e.g. integrations)

boilerplate and integrations are now mostly done through AI

Citation needed.

merge.dev, nango, composio.dev, all commodity alternatives to managing integrations, with varying degrees of handholding

Hah, if only SaaSintegrations were the hard part. Try integrating with insurance carriers!