I don't really buy this. In any modern language there's going to be pretty battle tested libraries out there to handle requests/response/decoding/encoding for

I don't really buy this. In any modern language there's going to be pretty battle tested libraries out there to handle requests/response/decoding/encoding for you. This is stuff that is almost never need to be debugged. If you have a small team and uncomplicated infrastructure, you're only hurting yourself by moving to microservices. However, if developer synchronization problems make core changes to your monolith difficult and block the work of a ton of people regularly, your monolith takes minutes to build or start up, and you're already having to shard the data your monolith deals with across many datastores, then there's no definitely no developer tax to switching to microservices.