The A-series chips are a genuine marvel for the devices they currently run but that isn't proof that the silicon will scale well for high-performance desktop parts. I would never believe their marketing fluff without some independent, platform-agnostic benchmarks; it certainly takes more than slapping on a HSF and cranking up the voltage to squeeze out linear performance gains. I'm cautiously optimistic that they'll have something rivaling their current high-end i9-Xeon offerings in a year or two. They're crushing the competition in the mobile space, so you've to give them some credit at least.
One thing that's certain is that Apple is steaming ahead with their One True Goal: total vertical integration of their hardware/software and gradual decoupling from the larger PC market. Apple wants very badly to avoid 1:1 commodity-style comparisons between their products and other offerings in the same product space because their entire business model relies on a significant profit margin on each item sold. It's much easier to market laptops when you've convinced your audience (rightly or wrongly) that you're the only company doing what you do.
I'd also argue that's a big reason they don't care all that much about the 'Pro' market, because by and large that segment actually does view computing power as a commodity. They just want a fast and reliable tool at a reasonable cost, interoperable with existing industry standards.
