People have asked for evidence on this thread, so let me share my experience. A couple of years ago, I was developing an E-Commerce platformm internally for my company. I follow Martin Fowlers' articles on using DDD (Domain Driven Design) and Microservices to architect applications. What should have been a month long project took us 8 months! I'm not including the time I took to read about, understand and practice DDD and the surrounding concepts. Every DDD book is atleast 500 pages or more. And none of them are clear on the concepts, and are mostly full of fluff.
To give you more details, our stack was based on Phoenix, but it used a concept called Umbrella applications (basically Micro services pattern). Along the way, I hit so many snags and I thought I must be doing it wrong. Because, that's what these authors kept saying all the time to people who had failed to implement their preachings. So, I met a couple of people who had actually done this DDD on a much larger scale than I had and even they shared the same experience and stories of failure and struggling. Still, I shrugged them off thinking it must be something we were doing wrong instead of DDD/Fowler's teachings itself. In the meantime, we were struggling to launch features for our E-Commerce software because our microservices architecture based on DDD was just a house of cards at this point. And then, I finally called up someone I knew who had done DDD successfully and asked him how he did it. He said one of the authors of a popular DDD related website, had offered to consult for his company. And they had no choice but to employ him because they were pretty invested at this point. After a while, I started meeting a bunch of such companies who got their DDD setup done by either authors or by some vendor these authors had a stake in.
And then BINGO, it all made sense - most of these patterns/shortcuts/discoveries/secret sauces by these authors are hardly tested by them. It's just a way to sell you more consulting and training.
A couple of weeks later, we hosted a casual meetup for tech talks in our area and we got to meet more folks who had followed the same path and failed. We finally decided to do a small hackathon over a weekend and get our projects done. In the end, in about 3 days from Fri-Sun, we had got done so much more with a monolithic architecture than we had ever gotten done with DDD and microservices. Today, my platform is in production and is a proud monolithic app and still going strong.
It was perhaps the most expensive lesson I've ever learnt, but one that I will remember for a long time.