I don't think OP was intending "minimal" to mean it would be easy to get to the stage where it's possible, just that once you've got all your infrastructure-as-code stuff set up correctly, you ought to be able to just be pressing buttons / running scripts and have your infrastructure up and running in another cloud provider.

Even when working in small companies with small infrastructure, I've kept recreation of infrastructure as one of my high priorities (one reason it really bugged me in one job to have to depend on Oracle Databases that I couldn't automate to the same degree.)

In my mind, it's not different from the importance of having, and testing restoration of, backups. If your infrastructure gets compromised somehow, or you find yourself up the creek with your provider, you've got to be able to rebuild everything from scratch.

No, with over 20 years experience and having done exactly this for several different companies and startups I pretty much have this process down.