One theoretical problem with this is that it's impossible to know for sure that a packet has been lost and there's no one-size-fits-all timeout to use. On most links it doesn't matter too much, but that may be the reasoning. I've seen ping times spike in excess of two minutes on real-world internet connections (abusing 1xRTT data through a RAZR back when those were still cool) and it was... if not useful, at least interesting, to know that the data wasn't actually being dropped but was just taking a really long time.