My conclusion, not enough servers at DirectTV.
That may be the case. On my measly 6 Mbps connection, a year ago I could download a 2 hour movie in about 30-40 minutes and it now takes three times as long.
You could also make a case that Direct TV has purposely slowed down the connection speeds to allow users with slower connections to be able to connect. As I mentioned, the wireless I was testing at the time was running at 5+ Mbps and the signal was barely adequate.
I do notice that Direct TV will no longer support wireless for the Whole Home feature, something they were doing during the Beta test, so the speeds on that setup have probably stayed up to normal.