Yeah but the lock-in wrt email is absolutely huge compared to chatting with an LLM. I can (and have) easily ended my subscription to ChatGPT and switched to Claude, because it provides much more value to me at roughly the same cost. Switching email providers will, in general, not provide that much value to me and cause a large headache for me to switch.

Switching LLMs right now can be compared to switching electricity providers or mobile carriers - generally it's pretty low friction and provides immediate benefit (in the case of electricity and mobile, the benefit is cost).

You simply cannot compare it to an email provider.