Millions (if not hundred of millions) of websites rely on jQuery, switching to a newer version that breaks old code will wreak havoc and make these sites unusable.
But this shouldn't stop jQuery from improving. If you have read the article from the beginning, you'll see how the jQuery team was improving the binding functionality. It has a cost, certainly. Maybe there should be a jQuery version with no legacy code.
They're deprecating stuff, so it's just a matter of time. I think that's the sensible way to do things.
http://blog.jquery.com/2011/11/08/building-a-slimmer-jquery/
They're also taking steps to be able and use Google Closure Compiler's advanced optimizations, which would let you build jQuery against your code and trim out everything that's not used. Pretty handy.
That is awesome, thanks for pointing it out!
These are just things off the top of my head. I feel like jQuery is the same as PHP when it comes to api, and I make a living doing PHP.
One way I solve the issue around overloaded apis is by not using them. I just pretend .click() and friends just don't exist.
$(selector').addEvent('click:relay(selector)', fn)