They aren't. For proof I give 50 years of this problem not being solved anywhere except text files effectively because text files have no structure except line

They aren't. For proof I give 50 years of this problem not being solved anywhere except text files effectively because text files have no structure except line feed. There is no universal format for formatted text. You could point to HTML but try exporting to HTML from Word and then importing back in and you'll see what's missing. There is no universal format for structured graphics. No universal format for raster graphics. No universal format for 3D. No universal format for spreadsheets. Etc..... They all have the same issue. There are infinite possible features and infinite possible ways to represent those features, each with their own tradeoffs.