The "good reason" is that modern web devs do not consider SQL a core skill, and plain do not understand databases. To be a competing modern web framework you have to include an ORM so these people will consider you.

Trying to explain to a modern web dev that the optimum data storage structure is not the same as the optimum application layer data structure, so you can't just take one and map them across 1:1 to the other, is really painful.

Developing without an ORM is just as quick as developing with one (because the time you save on routine queries you will more than lose on the tricky edge cases that the ORM completely screws up on). But you need to know SQL and databases to do it.