Before XML became a standard and given all its shortcomings, what made XML so popular?

Question

Yes XML is human readable but so is comma delimited text and properties files.

XML is bloated, hard to parse, hard to modify in code, plus a ton of other problems that I

Answer 1

Compared to some of the previous standards it's a dream. Try writing HDF (Hierarchical Data Format) files or FITS. FITS was standardised before the invention of the disc drive - you have to worry about padding the file into block sizes!
Even CSV isn't as simple. Quick question, whats the separator in a German CSV file?

A lot of the complaints about XML are from people who use it to transfer data directly between machines where the data only exists for milliseconds. In a lot of areas the data will have to last for 50-100 years and be far more valuable than the machine it ran on. It's worth paying a closing tag tax sometimes.