Why aren't there more visual programming languages? (An ode to DRAKON)

Larger Scratch projects have bogged down for me because there's so much panning left and right. I don't know that it'll work, but I have a small hope that some form of AR will actually make a difference with these types of visual UIs.

Semantic errors dominate syntax errors.

(that said, I've been adopting several Drakon ideas as layout suggestions for my traditionally-parsed algebraic language, but as aids to communication and comprehension, not for syntax hand-holding)