They are moving there because it's new and shiny, not because it's better.
Spring and Spring Boot are incredibly productive and give you a ton of stuff out of the box, whereas some people actually enjoy writing a lot of plumbing code as a distraction/challenge from boring business code. Those people will migrate to "lean" frameworks because it will give them the opportunity to write more low-level plumbing code.
Spring and Spring Boot are incredibly productive and give you a ton of stuff out of the box, whereas some people actually enjoy writing a lot of plumbing code as a distraction/challenge from boring business code. Those people will migrate to "lean" frameworks because it will give them the opportunity to write more low-level plumbing code.