One of the more interesting interview question I’ve been asked in the past few years was about the differences between cloud development and monoliths. I don’t think I gave the expected answer when I said that they’re not all that different
Yes, cloud environments are complicated but good cloud development relies on the sort of fundamentals that sometimes go wrong in monolith development.
Co-ordinating subscription renewals, credit card billing and confirmation emails is an example of working with distributed systems on a monolith. Do this in the wrong way and you billed a customer multiple times, or spammed their email. Trade-offs, failures and retries needed to be carefully considered.
A lot of applications take external systems for granted, rather than considering that they do sometimes go wrong. One place I worked coupled their login process to Salesforce. When Salesforce had an outage, their monolith shared it. When local filesystems have issues, applications will fail dramatically.
There are obvious differences between cloud and monolith development (not least the operational complexity), but both require an attention to the principles of software development. You don’t need a large system to be hit by the fallacies of distributed computing.