why i can only make three layers of nested quotes

[Drachenbauer]

Hello

i tried to quote a post with three layers of nested quotes in it.
But the most inner layer will not appear in my post.
if i try to add it manually, it just disappears at saving my post.

sample:

3

2

1

if i try to add a fourth quote to the center this pattern, it just disappears

why this is limited to 3 layers?

[Sašo]

Because quote pyramids used to be a fairly common problem back in the day. Long discussions would just cause massive blocks of text that was already posted and quoted multiple times, just making pages long and unreadable.

You could (and did) end up with stuff like this:

image.png

Not very readable.

To be clear, I believe most forum software added this as a feature long ago, so "back in the day" means ~15 years ago.