Aren't we? How many people's primary computing devices are ARM-based devices at this point? I know plenty of people who rarely touch a laptop, yet alone a desktop. Expansion of the computing market is mostly happening in developing markets through predominantly ARM-based devices too.
> How many people's primary computing devices are ARM-based devices at this point?
At home, it's a high percentage and has been for many years.
In office environments at work, it's still near zero (emphasis on primary). A couple hundred million people across middile and upper development nations use desktops and laptops every day at work. They're not going to switch to ARM systems anytime soon for that work. Good desktop processors are a few hundred dollars; ARM has no great angle there (including on pricing). For businesses the cost of a decent Intel or AMD processor is a modest share of the overall system they're buying for the employee to work with.
In developing nations with primitive economies, certainly smartphones are much more common for primary work purposes. And that's a case where ARM pricing does bring a huge advantage that Intel and AMD struggle to compete with. Cost obviously matters in personal businesses where your income is $50-$200 per month. Numerically this category wins, primarily due to the intense poverty of three billion people in India, Africa and China. This market alignment based on incomes probably won't change much in the coming decade, as ARM's ability to push into higher value office work environments as a primary will be very limited.