Backwards compatibility can be the bane of innovation. There are many instances where we are living with arcane systems or limitations simply because it was too cumbersome to break compatibility.

Deciding what are 'acceptable' limitations given current constraints vs 'planning for future expansion' is an art form. Unfortunately, too little thought is actually put into that decision in too many cases.

I remember working on a system (NetWare) when the server error code was a single byte. It didn't take long to run out and they started assigning the same error code to multiple conditions. The last one (0xFF) was so widely used, internal docs referred to it as 'something bad happened'.