Exactly my thoughts. Only one JS framework of that size. You'll probably include a few more JS (analytics and what not)... no wonder my "unlimited but limited" mobile plan is hitting the limit every month.
Artsy.net home page weighs 5.2Mb compressed. Less than 20% of that is JavaScript that is fully cached between page views. Let's suppose average visitor will watch 3 pages on average visit. He'll consume 800Kb of JavaScript and 12Mb of images. Most likely, next visit visitor browser won't download any JS at all. If people are OK browsing so image-rich website on their phones, developers shouldn't bother about 140Kb of Ember.JS if it helps them deliver app faster. JavaScript is less than 10% even for the first time visitor.
I don't know artsy.net, it's probably image heavy.
But an average webpage size of over 1.5MB is not acceptable onmobile, imo: http://www.websiteoptimization.com/speed/tweak/average-web-p...
Also: http://royal.pingdom.com/2011/11/21/web-pages-getting-bloate...
It's far more then it should be. Graphics can be size optimized, SVG or jpg. A JS framework doesn't need to be 100k where most webpages are probably only using a small subset of functionality. And i also don't want to download a gazillion other JS files for web tracking and such things. Ever download on a high latency connection hurts.
Even though you always hear about the mobile web, web devs simply aren't trying hard enough to make the mobile web experience pleasant. They'd rather complain about mobile safari or mobile chrome than actually look at their own product.
(Yes, this is a generalization, but generally, the mobile web sucks.)
Your problem is a mobile network operators' problem primarily and not web/mobile devs'. Don't blame us for making the experience for you or us all prohibitively mediocre when those carriers are to blame for their ridiculous limitations imposed on data consumption and their exorbitant data plans.