First they give you a ton of credits, assign you internal resources to help.

Then they encourage you to simply "lift and shift" your workloads onto EC2/EBS/EFS/etc. It's 100% compatible with your current system, you can rollback, etc. This take two years, then you notice your AWS bill is 10x your old infra.

Then they say - of course, that's because you need to rewrite it all to serverless/microservices/etc that are all AWS bespoke branded alphabet soup of services. Now you are fully entrapped, and can not rollback to your own infra, let alone another cloud provider without another rewrite.

A lot of big financial firms are 5+ years into this. Several have rolled back for certain use cases due to cost, especially anything with a lot of data transfer because yeah.. performant storage in the cloud & egress are expensive, duh.