What does "locked in the Apple ecosystem" imply? Apps that don't have a satisfactory equivalent on Android, integration between Apple devices or general usability/user experience?
That's relatively trivial to switch. If anything it would be the ecosystem of purchased applications that you still intend to use.
Other than that, nothing should really keep you "locked-in" on iOS. Not even iMessage. You can use WhatsApp or FB Messenger with friends or family. It's not a big deal.
I still like iOS better and don't intend on switching but the only "lock in" I feel exists is the years of sunk cost I have in purchased apps I still use.
I would disagree about iMessage though. I have older family members on iOS that would not use another messaging or video chat app. Our chat experience would simply degrade to stock SMS.