I absolutely agree that the main issue is that the system can't be improved by competing concepts. The development model is really important - what started as a private hack became a designed-by-committee mess, and now is starting to become more sane in the age of HTML5, as new useful technologies and APIs are being added. The big issue is CSS (and Javascript is only slowly becoming better), which stems from the designed-by-committee (with bad taste) era - if it was designed today with Google etc. at the table, it probably would be a lot better.

People try to work around that by using pre-compilers like LESS and CoffeeScript, but those cannot fix the underlying issues. If people could design their own CSS engines, the development model would allow for rapid iteration and whatever people like the best would see broad adoption.

Reminds me of the BPF packet filter bytecode - limited, but fast and secure.