Searle has stood behind his argument in the 70s, but in every decade since then too.
The main failure is that most people fundamentally don't believe they are mechanistic. If one believe in dualism, then it easy to attribute various mental states to that dualism, and of course a computer neural network cannot experience qualia like humans do.
I don't believe in a soul, and thus believe that a computer neural network, probably not today's models but a future one that is large enough and has the right recurrent topology, will be able to have qualia similar to what humans and animals experience.