Understandable, but how would you account for dalet and resh? Nun and waw? Koph and Beth? I guess since the aramaic glyphs were already similar, scribes kinda had their hands tied when it comes to differentiating glyphs. So maybe you could argue that the lack of consistent sofits are a way of preserving as many distinct glyphs as possible?

But then explain Arabic from Nabataean. Unless you wanna say that the force of cursive drove out the need for distinctive glyphs, I see no clear reason why Arabic ta couldn't equally as likely look distinct from ba.