'the Internet Engineering Task Force decided not to make it backwards-compatible, which has somewhat hampered its adoption.'
Because backwards compatibility is such a success.
Windows - Microsoft has been trying desperately to lose backwards compatibility because it makes a dog's breakfast of their operating system. But it's also the only reason anyone buys it.
USB - Gone from a standard, to two standards on one set of wires, to two sets of wires in one cable and a ludicrous two-tier plug that's nearly got enough pins to be a parallel port.
PC - A crazy stilted architecture still carrying the baggage of a 35-year-old processor.
Sometimes you just need to do it again and ditch what went before. You can't just keep adding layers.