The lock-in is around identity services, right?

Servicing the jobs-to-be-done of the core applications is pretty straightforward I think.

I'm not sure what keeps people locked in besides identity. Article doesn't really specify.

Familiarity, convenience and habit.

Familiarity: "I've used MS Word/Excel/Teams before so I can use it here"

Convenience: "We have MS Entra, might as well go all-in"

Habit: "We never really investigated alternatives, this is just what 'everyone' uses."