If SD is unwatchable, how did people get by watching SD for fifty years before HD became available?
However I agree that Directv's SD is pretty bad. On local stations that broadcast in SD I get a much better picture with my antenna than I get from Directv. It isn't as good as HD of course but it's better than Directv's equivalent.
Stretching SD to 16:9 doesn't help for some. There are consumers who still hate any letterboxing done to movies.