All those symbols are necessary for readable math though. For millenia people did math as you describe, and it worked very poorly compared to modern math notation.
For example, how would you write something like a tensor H_i^{kl} (pretend those are rendered sub and superscripts)?
Looking at that symbol, I immediately understand that H is a tensor with one lower index and two upper. Now, it precise words, it would probably be something like:
"Let H be a tensor with lower index i and upper indices kl."
Oh wait, we've already had to define all the variables anyway (since we don't want to specialize it to an individual tensor, because that would be useless). Why not just use a bit more notation and write it as H_i^{kl}?
If we ran out of letters, we'd have to use Greek ones. Now we are back to where we started.
For example, how would you write something like a tensor H_i^{kl} (pretend those are rendered sub and superscripts)?
Looking at that symbol, I immediately understand that H is a tensor with one lower index and two upper. Now, it precise words, it would probably be something like:
"Let H be a tensor with lower index i and upper indices kl."
Oh wait, we've already had to define all the variables anyway (since we don't want to specialize it to an individual tensor, because that would be useless). Why not just use a bit more notation and write it as H_i^{kl}?
If we ran out of letters, we'd have to use Greek ones. Now we are back to where we started.