An iOS app would require not only rewriting an entire website to be native to iOS (or using something that compiles into something workable with both iOS and Android) but also rewriting the backend to be compatible with the same system. Since the current architecture is over a decade old, that'd be far too painstaking for just the current small team that we have currently.
It's not "transferring", it's "rewriting". That'll take a lot of time, which isn't really something that we can do. Unless you want to do it for us.