I think we have to take into account that Ruger's new line of pistols, the SR9, 40 etc. are relatively new. Previously their guns were deemed too large clunky for CCW etc. Their semi-autos have never made it big in the LE Community and a lot of people like to go with guns that have been vetted for by the LE community.
When it comes to the SR9 and SR40, I do not think they are in the same league as the others you mentioned. I think Ruger could have done things a little differently with the guns and had a better result. The sights on the SR9/40 are lack luster, there's no stink'in reason to put adjustable sights on a pistol of that sort, the safety IMHO is too small, I think Ruger chose the size specifiaclly to be able to meet some legal requirements in nanny states and placate those that like the safety, at the same time making it small enough not to bother those that wouldn't use it. I think it's too small to be used as a safety while carrying and I've seen a lot of people have trouble with it and a lot of people that like striker fired pistols don't like external safeties.
The LCP was an easy success as it took an all ready successful design and improved on it slightly, and the LC9 is running on the coat-tails of that "borrowed" design.