I think Kiro might have some “first mover” advantage internally, but CC feels better to use.
GitHub Copilot is in a somewhat similar place as Microsoft's toy but still different -- it was more or less the first coding agent/assistant, and GitHub/VSCode/Microsoft has enough user base and impact to influence individual users and enterprises' choices.
For Amazon's coding agent -- I just never see anyone outside Amazon even mentions Kiro or Amazon Q. Maybe a little bit when Kiro was offering tons of free credits. But I don't think it's even remotely relevant these days. I don't see news about companies adopting Kiro.
To me, it's just a matter of time before they are sunset, like Chime or a bunch of AWS products.
For Kiro, I agree with you, it seems like wasted effort and Anthropic / OpenAI are miles ahead in their tooling.
I love AWS at the infrastructure level, but their PaaS tends to be meh, and their end-user directed stuff is usually atrocious.
They were a manufacturing org and only managers had licenses to MS Office and users in Active Directory. Everybody else was registered on a separate OpenLDAP directory to avoid paying MS licenses.
Chime was cheaper per user than onboarding everybody into AD and paying Teams, and they could tack Chime usage into their AWS bill.