Almost everyone is making native mobile apps — two copies of the same thing, for Android and iOS — but for desktop, it's suddenly something infeasible? Why so?

Almost everyone is making native mobile apps — two copies of the same thing, for Android and iOS — but for desktop, it's suddenly something infeasible? Why so? It has always been other way around in my mind — my phone is an auxiliary limited communication device that's awkward to type on. Yet for almost every IT company with a mainstream product, phones are first-class, and computers are an afterthought. How so?