When you are at a team of 50 working on 40 separate services with 500 Lambda's or so I don't see how you are better off than writing a self contained service that's deployed as a single artifact i.e microservice.
You get the advantage of all related code grouped together, easy to instrument / test / run on any platform. All the advantages of a mono repo but at a service level, non of the orchestration or special tools to deal with 500 disparate lambdas and wiring up event sources / sinks.
I think the complexity aspect is a fair criticism of Lambda.
The way I look at it is that, as a developer, I want all the advantages of serverless (per ms billing, scaling up instantly, scaling down to 0, etc) while not having to worry about the function level nuances of tooling and deploying.
Having struggled with scaling large systems in a past life, I personally lean more towards taking on the burden of tooling instead.
If you use a few sparingly, great.
When you are at a team of 50 working on 40 separate services with 500 Lambda's or so I don't see how you are better off than writing a self contained service that's deployed as a single artifact i.e microservice.
You get the advantage of all related code grouped together, easy to instrument / test / run on any platform. All the advantages of a mono repo but at a service level, non of the orchestration or special tools to deal with 500 disparate lambdas and wiring up event sources / sinks.