For starters, the title here is extremely misleading especially now that we’re in GSoC season, but the simple answer to this entire topic is this: due to most of this project being done on volunteer work and the main dev team being extremely small, the complexity of implementing these features outweighed the amount of time and resources available to implement them. It’s also something that only really recently started getting requested again and is being looked at as possible GSoC project submissions.
Note: I’m a mentor here but not one of the devs. I’m just more of one of the people guys here to help answer questions like this along with direct users to information and whatnot.