That's my general impression. As Rails grew in popularity and was used for more and more complex things (with more and more complex database tables), they start

That's my general impression. As Rails grew in popularity and was used for more and more complex things (with more and more complex database tables), they started to add in the raw query building parts of ActiveRecord. Though I think it was more that they wanted raw query functionality in the library and it made most sense to enhance the tool that already dealt with the database rather than add another alongside it.