It's just not worth it until your monolith reaches a certain size and complexity. Micro services always require more maintenance, devops, tooling, artifact registries, version syncing, etc. Monoliths eventually reach a point where they are so complicated that it becomes worth it to split it up and are worth the extra overhead of micro services, but that takes a while to get there, and a company will be pretty successful by the time they reach that scale.

The main reason monoliths get a bad rap is because a lot of those projects are just poorly structured and designed. Following the micro service pattern doesn't guarantee a cleaner project across the entire stack and IMO a poorly designed micro service architecture is harder to maintain than a poorly designed monolith because you have wildly out of sync projects that are all implemented slightly differently making bugs harder to find and fix and deployments harder to coordinate.