No one can say if it was "as large as possible." It's at least plausible he left money on the table with some missed opportunities.
For example: handing over the semi-pro video creator space to YouTube. Apple already a thriving podcast ecosystem, but failed to capitalise on it. There was a real opportunity for vertical integration with Apple selling hardware, targeted content creation software (a CapCut-a-like version of FCP), and access to a distribution network.
Also, home automation and security. Cameras, switches, maybe even routers with local backup. Not sold as devices, but as high quality services with obvious benefits that happen to run on specific hardware.
AI: there was the opportunity to develop Siri into an agentic assistant well before anyone else got there.
Cook's slant was more towards chasing high-end Veblen lifestyle status - cars, watches, premium computers and phones - and less towards social marketing and less shiny but useful consumer devices.