Not really true, lots of lurchers have started from bitch collie, bull, saluki, deerhound etc etc etc and a greyhound sire, because the traits of the dam are required with more speed.
Yes but are they any better for it? Having seen some of these crosses I stand by what I said and that a lot of them would be better dogs if they had a bit more greyhound in them. I have mates that are breeding little more than mongrals and think they are running dogs.