My employer has lots of poorly factored monolithic code. Around three years ago, microservices and microsites were chosen as our new design pattern for the future. Cue the following three years spent redeveloping specific parts of the monolithic beast with the goal of eventually replacing the monolith with elegantly composed service and microsite parts.
To date I estimate that we have converted at most 5% of the monolithic beast to our new service based design pattern. It was clear from when the first service and microsite was delivered that it was horribly expensive to develop and maintain. During those three years, regular business churn requirements continued to be delivered as expected and over time the separation of concerns, the positioning of business logic and the definition of interfaces between the new parts and the monolith degraded to unfathomable levels of incoherence and complexity.
The plan to continue on with that design pattern has now been stopped in favour of doing something new from scratch and although this new thing will still be a service pattern crusade, it is going to be developed in a language that virtually no employee has any expertise in. To be fair I do understand the reasons for wanting to iterate towards a scaleable services design however the company culture gives me confidence that the new idea is also destined to decline into insanity.