From what i understand/ have read Larian is focusing on difficult thing first, leaving easy fixes like spell learning towards the end.
There are no recorded public statements from anyone at Larian that give credence to your statement.
There is, its from a interview that was recently posted. I'm not going to go digging for it, but it's on these forums. Sven mentions the reason they did druid class first was because it was the most difficult.
Edit* I'll throw my hat in the main topic, there used to be a skill for 3.5 where if you sank points into it you could cast scrolls. In 5e I don't know off the top of my head how it works but I can't imagine someone with a lack of knowledge / attribute points will be casting high level scrolls if they have to roll for it, but who knows what they'll do.
