Use of icon fonts by social networks

Question

css

It is interesting to hear the opinion of experts from Habrahabra, and possibly representatives of the social. networks.
Why do you think trending social networks such as Facebook, VK, Twitter, Badoo, Orkut, Google+, Foursquare, etc. don't use web fonts, and web icon fonts in particular for their icons?

Answer 1

Custom fonts can unload unpredictably in chrome and are not supported at all in Opera Mini

Answer 2

I can recommend a couple of articles on the topic:
css-tricks.com/svg-sprites-use-better-icon-fonts
ianfeather.co.uk/ten-reasons-we-switched-from-an-i...