Sadly one way to look at this might be similar to "the number of people who can drive an automatic transmission and change their own spark plugs is decreasing." Its true, but the underlying tech is changing too, so is it really a problem?
Applications being able to assume that you have a keyboard, mouse and big screen really allows them to create way more powerful interactions while any tool made for a smartphone will be severely hampered by its UI limitations.
Exactly, so more people than ever know how to use computers.
Seems like a great benefit that they don’t have to deal with all the unnecessary complexity.
Being forced to learn enough computers to log on to your bank doesn’t make you more employable.