You are correct that currently, Desktops and Laptops outnumber mobile devices for the majority of traffic (varies by site, of course).  However I have personally witnessed a nearly 20% year over year jump on mobile traffic on several sites which I have traffic data for.

That said, while Apple is a huge majority in the U.S.  it's actually the minority world wide.  Android regins with 70~% of the market.  

Because of the concept of technical debt, it actually makes sense to start adjusting sites now prior to the point in time mobile traffic exceeds 50% of total site traffic (which for a lot of sites, is coming up, if not already here).