TODAY, Xojo has a nice Web app product but it has got wrinkles, in a Web world that has considerably evolved. That said, it remains very relevant as a complement of desktop solutions, especially for programmers that have zero web skills and wish to port their applications to the Web with minimum pain.
I doubt extremely much a client layer is even in the air.
In the short term, they better make sure iOS gets fast on par with the Desktop. It seems to be on the way.
Medium to long term, mobile will never go down.