Haha, I just went to get rid of my Mom's sunflower imac. The geekbench on my phone is 10 times higher than that machine.
The direction things are going is the convergence of desktop, laptop, and phone in my opinion. You walk up to any monitor, mouse, and keyboard "station" and your phone connects wirelessly and instant to all of them. All your files are there instantly because they are either on your physical phone or in the cloud. You walk away and go to another "station" and it all connects and you pick up exactly where you left off with the same apps open and the cursor and mouse pointer in the exact same spot they were, ready for you to continue. And the "phone" never left your pocket.
One version or another of this vision has existed since the 60s. I think the issue all along has been standards and interoperability. The issue has morphed of course, but in essence it is always the same.
As a consumer of this superconverged device, how do you shop for which system is best for you if not all "stations" will be compatible with your device? As a purchaser or operator of these "stations," how do you select which devices to support and in which categories.
We can't even get all the companies to agree on a which plug to use to supply basic power - let alone all the interfaces required for the type of "station" you're describing. It's not a unique issue, we can't agree on a charging standard for EVs either. Heck, most countries can't even agree on what type of fuel to use for cars or which type of plug to use for AC electricity.
And before someone chimes in the "USB," as the answer - it's not. Among many problems, USB as a standard setting organization has done a pretty poor job of it and is constantly fiddling with the standard to the point of where they can't get out of their own way. Further, how comfortable are you with letting the huge corporations in charge of the USB consortium own such an important standard?
The argument might also go that this reluctance to standardize is a good thing. Standards hinder innovation and discourage feature differentiation. It is a 100 times more difficult to disrupt an industry which has been standardized because there is almost no room through which to drive a wedge - if you're standard compliant then you can't stand out, if you stand out then people will be unwilling to stray from the standard.
So I think this vision for a "station" anyone can use and have all their files and apps on will continue to elude us until computation and computational power become a commodity like potatoes and we don't really care anymore. Probably not in our lifetimes.