well, the other factor is that -real- stalwarts have, at least, an X360 to play these games on and, for the real players, a supergun/arcade machine and the boards themselves.
You have to look at them for what they are : extremely good versions of cave games with alternate control schemes that are fun to play in their own right. Cave did a fantastic job on the iOS games, really top notch stuff.
Again, the difficulty is that the shmup arm of Cave is pretty much dead with the departure of key staff and the traditional shmup market place is also not in the healthiest of states - it's great that they can pump out a few iOS games and fill up the coffers a bit but the lack of arcade/home -traditional- games still smarts for those invested in that side of the hobby.