Very similar, yes.

Except that Kay did not envision the distinct computers communicating via REST.

https://blog.metaobject.com/2019/11/what-alan-kay-got-wrong-...

Also: microservices currently require at least process and frequently even VM/Container/Machine boundaries.

In-Process REST scales that down:

https://link.springer.com/chapter/10.1007/978-1-4614-9299-3_...

Language support for In-Process REST:

https://dl.acm.org/doi/10.1145/3359591.3359729

https://objective.st/