The companies/stacks Fowler encounters are generally in a problematic state. Thoughtworks, like other consulting companies, is generally hired when things are already going wrong. If they are hired to assess a broken monolith stack, the refactoring to microservices is naturally going to yield positive results, and it's easy to come to the conclusion that microservices are an improvement when refactoring from a monolith stack. When they are hired to assess a broken microservices stack, it's easy to come to the conclusion that starting with microservices is broken. What they don't usually see is the hundreds of instances of microservices (and monoliths) working as intended, as there is typically no need to call in a very expensive consultant in those cases. How many times in the case of badly-organized Microservices was the solution to migrate to a single monolith? I imagine the solution is more often to re-organize the services. If that's true, then one cannot say that microservices-first fails -- just that badly-organized microservices-first fails.
Starting with microservices first, especially in a small team of developers (but more than 1), helps things move much quicker than it did with everyone sharing responsibility for the same codebase. Organizational structure tends to reflect its products' structure. Microservices requires that the splitting of responsibilities between teams or developers roughly matches the split of responsibilities among services. Otherwise, you're just working on micro-monoliths.
An actual study needs to be performed before deciding on a "Right Approach" as this piece does.