I've got my Motorola modem right here, it has all the fancy compressions :) But no one was checking CRLs in those days either.
Seriously though, it's more about latency than speed, which can actually be higher on mobile compared to dial up. Which starts being a problem if you need to open two connections (one to the target site, one to the server hosting the CRL) every time.
BTW, the only platform that implements these things reasonably well is Windows, but it took them quite a while to get there.
Also I am working on the documenting decisions part, but it's slow going...