Unless you're paying by the byte, what gets downloaded shouldn't concern you from a well-developed site that doesn't hang on your phone.
Unfortunately, in this copy/paste era, too many sites shoot themselves in the foot.
The cause of the concern should then be addressed, not the person having the concern.
1. most developers aren't good, or at least not paid well enough to do what they consider a good job.
2. you cannot deliver web-fonts taster than you can deliver a page without web-fonts. Web-fonts will always be driving latency. On average in a noticably annoying way more often than not.
Besides... Downloading a 1MB font to render some typical 4kb of text? What sort of madness drives this behaviour?
I can definitely see the potential for a web-fonts blocker extension, like I now have ad-blocker and in the past had a flash-blocker (which now no longer seems needed).