Yes, As per official statement : from September 9, 2019: Account Kit will stop integrating with new apps. Existing integrations will continue to function normally.
Source 1,2
Does anyone know why they deprecated it? Any technical
insights/learnings?
"The product has yielded high maintenance costs, but relatively low adoption". Read full details here.
What are the alternatives now? or are they planing any successor of
it?
They not announce any successor for it as far as i know, but there are many other alternatives available as open source which obviously have certain limitations. What I am using currently will mention here.
- True Caller SDK : It require true caller app to be installed in user device.
- Firebase Phone Authentication
- Third Party SMS API : Obviously, it would be a paid api, Many service providers are available in market. I am not promoting any one here but one is suggested by google itself here called twilio. Just a extra point : In this 3rd case, for understanding the flow "SMS Retriever API" may worth reading for some one.