Why aren't ISPs providing stratum 1 NTP service?

I just crossed the 200th machine syncing of one of my stratum 1 servers. I like providing the service and it doesn't cost very much for me to offer the service. the problem I have with this is that NTP hates asymmetric routing, so the likelyhood is that for most people outside the provider that serves this machine, NTP time is suspect. It seems to me that the days when running a GPS refclock into an NTP server was exotic are long past. Why don't providers give NTP stratum 1 service to their customers? Then I can at least shed some of the most suspect clients (it's the routing path not the user that is suspect.) In search of good time for all, Jerry