I would argue that it would be nice that everything that has a CPU and RAM is a general purpose computing device, but just because it is nice doesn't mean that

I would argue that it would be nice that everything that has a CPU and RAM is a general purpose computing device, but just because it is nice doesn't mean that it is reality or an effective use of products. If we arbitrarily classify things based on what we desire instead of how they are brought to market, we might as well stop classifying things at all. As for 'general-purpose computers in our pockets', they exist, and they are brought to market as such for about two decades. They did however not turn out to be useful or viable.